Lord Derby’s Woolly Opossum. Colombia, November 2025

I find the marsupials of the Americas fascinating. The opossums with their long rat-like tails cannot compete in the cuteness stakes with the possums of Australia. Although I have been to the USA many times (to sit for hours in a darkened lecture theatre) and the countries in Central and South America, until Colombia in November last year I had never seen an American marsupial. Then along came three species.

A delight of a mammal-watching trip* as opposed to a birding one is the greater emphasis on night spotting. Birds, reptiles, amphibians and invertebrates are seen as well of course. On our first night walking along the road through the Otún Quimbaya Sanctuary on the western slope of the Cordillera Central we saw this Derby’s Woolly Opossum (Caluromys derbianus) by the light of the spotlamp. It is a terrible photograph since I had the camera set for a bird before darkness fell and pressed the shutter release anyway in the hope of getting something on the camera’s sensor.

Derby’s Woolly Opossum occurs from Mexico through the countries of Central America and then as far south as Ecuador. The alternative name of Central American Woolly Opossum as used in the IUCN Red List therefore seems misleading. In Colombia we were seeing the animal at the eastern edge of its range since it is confined by the Cordillera Central to the Cauca Valley. The river Otún flows westward into the Cauca.

The species was named for the well-known politician and zoologist the13th Earl of Derby (1775 – 1851) who had a large menagerie and museum at Knowsley Hall near Liverpool. Seeing his eponymous opossum in South America or his Derbyan Parakeet in the wilds of Sichuan in China does feel incongruous—and very unLiverpool.

On the other side of the Cordillera in the Magdalena Valley we saw a Brown-eared Woolly Opossum (Caluromys lanatus) briefly before it disappeared behind a tree trunk. 

Another species at Otún Quimbaya was the Common Opossum (Didelphis marsupialis). It was around the lodge and restaurant at the end of the road. We saw the same species on the rafters of our accommodation at Hato La Aurora in the Llanos, the wetlands of north-eastern Colombia. 

Opossums often produce more offspring than mammary glands. Therefore any that do not find a teat in the female’s pouch die. As in marsupials generally the young remain attached to the teat for virtually their entire development.

I did not know opossums were popular items in the human diets of the Americas, from the USA southwards. I cannot say I fancy the idea.

*Naturetrek’s Colombia’s Endemic Mammals

Edward Bosc Sladen’s eponymous animals from the 1868 mission from Burma to Yunnan

Sir Edward Bosc Sladen spent much of his career as a soldier/colonial administrator/diplomat in Burma. He was the natural choice to lead the mission to Yunnan in 1868 which was sent to explore the possibility of establishing a trade route between British India, Burma and China and on which John Anderson was the medical officer and naturalist. At the time of the mission to Yunnan Sladen was a Captain in the (British) Indian Army and In 1866 he had been appointed agent of the chief commissioner in Mandalay. In that year he narrowly escaped insurgents who had murdered three of the royal princes. During the subsequent disturbances Sladen gathered nearly all the Europeans and ‘other christians’ on board a steamboat and and evacuated them safely to Rangoon. After his return to Mandalay he persuaded the King of Burma, by then only in control of ‘upper’ Burma, not to execute three young princes. Only two survived, the third having been beheaded before news of the reprieve. After that he obtained the King’s assent to a new treaty covering commercial activity and extradition. It was against this background of hard and soft power that Sladen was chosen to lead the mission to China in 1868 described in David Leffman’s A Murder in Yunnan.

Sladen was born in Madras in 1827* to Dr Ramsey Sladen, Physician General of Madras in the East India Company, and his second wife, Emma Bosc. After Oswestry School he became a cadet of the East India Company in 1849 and on returning to India was appointed subaltern in the 1st Madras Fusiliers, a European regiment in the Company’s army. He served in the 2nd Burmese War. In 1853 he was appointed an assistant commissioner in Tenasserim. He was severely wounded during operations against insurgents in 1856-1857. In 1858 it was back to regimental duties. His regiment was heavily involved in the relief of Lucknow and further operations against the ‘mutineers’ in Oudh. Once back in Madras, Sladen reverted to the work of a district officer in Burma. The Staff Corps formed in the three Indian armies in 1861 enabled eligible officers to take up civil and political placements. When the 1st Madras Fusiliers became a royal regiment (i.e. a British Army regiment in India) Sladen became a member of the Indian Staff Corps but in 1878 still appeared in the Army List as in the Madras Staff Corps.

Captain Sladen of the Yunnan mission was promoted to major in 1869 and lieutenant colonel (without the hyphen in the modern style) in 1875. From 1876 until 1885 he was commissioner for the Arakan division. Then he was chief political officer to the force sent to depose Hing Thibaw in ‘upper’ Burma—the third Burma War. On 28 December Sladen arrived with the British troops sent to Mandalay. He entered the royal palace and took Thibaw’s surrender. The whole of Burma then became part of the Raj. Sladen was greatly praised by the viceroy for his courage and knowledge of the people of Burma. In 1886 Sladen was knighted and retired to England in 1887.

Sladen married Sophia Catherine Harrison in 1861; she died in 1865; they had a son and a daughter). Fifteen years later he married Kate Carew of Carpenders Park, Hertfordshire, in London; they had a son.

Sladen died in London on 4 January 1890, aged 63. He was living at 30 Lowndes Square, Chelsea. Newspaper reports provided the level of detail required by Victorian readers. 

We also have to announce the death of Colonel Sir Edward Bosc Sladen, which took place of pneumonia, after a very short illness, in Lowndes square, on Saturday night. He and Lady Sladen were present at the Marchioness of Salisbury's ball on the 20th ult., but on returning to town next day he found himself attacked with the influenza epidemic which is now so prevalent, and which culminated in the disease to which he succumbed so quickly.

The press, following the money, also reported:

…The late Sir Edward was in receipt of a good service pension for distinguished and meritorious services; had the Indian Mutiny medal with clasp for Lucknow, and the Burmah medal with clasp for Pegu…

John Anderson who served as both medical officer and naturalist to the 1868 mission clearly thought highly of Sladen. H e named a number of species for Sladen as well as suggesting his name to those who he asked to work on the insects and fish collected during the trip. Those names have of course been subject to many later revisions of taxonomy and have either been entirely subsumed as synonyms into other species or retained as subspecies.

THE RAT

Anderson’s Mus sladeni, latter Rattus sladeni is a species I have written about previously. The original—but not necessarily those rats from other parts of Asia that came to be known as Sladen’s Rats—is now lumped in Rattus tanezumi, the Asian House Rat.

THE SQUIRREL

A Sladen eponym missing from the Eponym Dictionary of Mammals is Sciurus sladeni. This beautiful squirrel is now lumped into Pallas's squirrel (Callosciurus erythraeus) which has major geographical differences in coloration. Some schemes retain the subspecies C. e. sladeni.

THE PHEASANT

Also missing from the books on avian eponyms is the pheasant Phasianus sladeni, now regsrded as a subspecies from northern Burma of the Common Pheasant: Phasianus colchicus sladeni.

THE FISH

Anderson appears to have handed over fish collected during the mission to Francis Talbot Day (1829-1889) a fellow medical man who became Inspector General for Fisheries in India. He named a freshwater fish for Sladen but got the name wrong: Salmostoma sladoni. Interpretation of hand-written labels after immersion in spirit is not easy.

THE TIGER MOTH

Frederic Moore (1830–1907) who worked at the East India Company’s museum in London sorted the insects. He named a tiger moth for Sladen: Syntomis sladeni. It survives as a full species, Amata sladeni.

- - - - - - - - - - - - - - - - - - - - - - 

I thought that is all I had to write about Sladen and his eponymous animals. However, I now find that his son had a major role in a great public health problem of the 19th and 20th centuries. Edward Sydney St Barbe Sladen was medical scientist, soldier and zoologist, I can argue that I would not be sitting where I am today had he and his colleagues not tackled a zoonosis that still costs the UK millions of pounds every year to combat.

The colour plates are from: Anderson J. 1878. Comprising an Account of the Zoological Results of the Two Expeditions to Western Yunnan in 1868 and 1975 and a Monograph of the Two Cetacean Genera, Platanista and Orcella. Second Volume - Plates. London: Bernard Quaritch.

White-browed Spinetail of the Colombian Andes

This White-browed Spinetail (Hellmayrea gularis) was searching the bark of trees—and taking proffered mealworms—at Hacienda El Bosque, a popular birding lodge at an altitude 11,000 feet (3,350 metres) in the Cordillera Central of the Colombian Andes. It is one of many species in the Central and South American ovenbird family, Furnariidae.

This species is found in damp forests along the Andes from Peru, Ecuador and Colombia to Venezuela at altitudes from 2,300 to 3,900 metres

A Murder in Yunnan by David Leffman: a book - and the zoologist, John Anderson

David Leffman has written a cracking book on the murder of a British diplomat, Augustus Raymond Margary, in China near the border with Burma on 21 February 1875. He begins by outlining the problem of finding out whodunnit:

Margary may have been beheaded. Or not. Perhaps he shot one of his attackers before being killed, though this same man - or somebody that officials claimed was the same man - later denied it. Margary's Chinese servants all died alongside him, or were picked off elsewhere, or one of them escaped. The attack happened inside Mangyun at a banquet, outside the town on the way to some hot springs, or up in the far-off hills.

His killers were regular Chinese soldiers, lawless bandits, tribal "savages", former Muslim rebels or a civil militia; they might have been led by a warlord, were acting independently, were under orders from the Chinese provincial governor, or were obeying the wishes of the Burmese king. The men arrested for the crime all confessed their guilt, or they were innocent villagers whose admissions were fabricated by a court interpreter. It's possible the interpreter himself was the murderer.

So whose version of events to believe? …

I will leave the story for you to read in David’s book. The background which he describes, having sorted out everything from modern places names to all the people involved called Li, was that Margary was moving ahead of a what is perhaps best described as a political mission looking into the possibility of opening up a trade route from British India, through Burma, to southern China. It was led by Colonel Horace Albert Browne (1831-1914). It turned back when attacked after Margary was killed by a large band although who the assailants were working for can be discussed along just the same lines as trying to work out who murdered Margary. The attack was repulsed. The squad of fifteen British Indian Army Sikh soldiers specially selected to escort the mission earned their pay and praise.

The medical officer/naturalist for the mission was Dr John Anderson. Anderson had the same role in an earlier mission with the same purpose and through the same country in 1868 that was led by Colonel (later Sir) Edward Bosc Sladen (1831–1890) and it was Anderson who wrote a an account of both missions in his book, Mandalay to Momien: A Narrative of the Two Expeditions to Western China of 1868 and 1875 under Colonel Edward B. Sladen and Colonel Horace Browne.

I have come across Anderson before since he named a rat collected in the first expedition for Sladen. The identity of that rat and probably wrongly identified as a species occurring in Hong Kong I discussed HERE. But who was John Anderson?

John Anderson 

John Anderson was born in Edinburgh in 1833. Both he and his elder brother, Thomas, were interested in natural history and both worked in India for a part of their lives. On leaving school John worked for the Bank of Scotland. He left in order to study medicine ,like his brother. Also like his brother he became more interested in the basic biology part of his education, in his case zoology and comparative anatomy, in his brother’s case botany. Over this period John dredged for crustaceans and other marine organisms in the Firth of Forth and described their morphology and proposed changes to their classification. He presented his work to the now extinct and poorly named Royal Physical Society of Edinburgh and published his findings in the Annals and Magazine of Natural History. He also included it in his M.D. thesis on nothing medical but entitled Contributions to Zoology. For that he was awarded a gold medal at his graduation rom the University of Edinburgh in 1861.

One paper began with:

Three years ago, I drew the attention of this Society to the fact of the frequent occurrence of Sacculina and Peltogaster on some of the Crustacea of the Firth of Forth. For some years past the subject of the affinities of these parasites has been occupying the minds of many foreign observers; and the following observations, therefore, are brought before the Society in the hope that they may tend to throw some light upon this difficult question…

In 1863-1864 he was professor of natural science at the Free Church College, Edinburgh (now the Edinburgh Theological Seminary). He left there for India.

I am slightly confused because notes on him from the Royal Society of Edinburgh show he was employed by the Indian Medical Service for his entire 21 years in India from 1865. If so then we can only assume that the post to which he was recruited was allocated for administrative purposes to that service. The background to his appointment in Calcutta was that the government  of India (the Raj) had taken on the collections of the Asiatic Society of Bengal to form the nucleus of a museum. The government in India asked the Secretary of State for India in London to find somebody suitable for the job of curator. Anderson was appointed and a few years later upped in status to Superintendent. In addition he became Professor of Comparative Anatomy at the Medical College, Calcutta. He held both offices until his retirement from India in 1886. The present building was completed in 1875. When we visited the museum in 2007 we made straight for the zoology collection. We suspected it had altered little since Anderson’s day. The legs of each cabinet of stuffed animals stood in a small trough of water as was always advised in the tropics to prevent destruction by insects. Later we crossed the Hooghly by the Howrah Bridge and visited the botanical gardens where Anderson’s brother Thomas had been Director in the 1860s before returning ill to Edinburgh where he died in 1870, aged 38.

It was while curator of the museum that John Anderson was medical officer and naturalist to the two missions to Yunnan.

Having written general accounts of both missions he turned his attention to the animals he had collected. He described them in papers and in a book that put them alongside other Asian animals: Anatomical and Zoological Researches: Comprising an Account of the Zoological Results of the Two Expeditions to Western Yunnan in 1868 and 1975 and a Monograph of the Two Cetacean Genera, Platanista and Orcella. He didn’t go in for short titles. Nor short volumes since that was published with the text, over 900 pages, in one volume and the plates in another.

Anderson collected specimens whenever he could but apologised:

It is necessary that I should here give a short account of the two Expeditions, in order to bring out the difficulties with which I was beset as a naturalist, and which, to my great regret, were of so formidable a nature, that they restricted my investigations within the narrowest limits in a country the fauna of which is extremely rich and all but unknown.

The First Expedition was despatched in the end of 1867 from Calcutta, and returned in November 1868; and the Second Expedition left Mandalay on the 3rd January 1875, and returned thither on the 10th March of the same year.

By the permission of the Trustees of the Indian Museum, my services were placed at the disposal of the Government of India to accompany the two Missions as Naturalist and Medical Officer.

The ‘difficulties’ were indeed great as David Leffman covers in his book. Survival was not guaranteed on a mission opposed by two central governments and local vested interests.

I will return to the animals Anderson collected below other than to point out here an unforeseen problem with pickled reptiles during the first mission. The largely Muslim Panthay Rebellion (1856–1873) was in full swing in south-west Yunnan and followers occupied key towns and villages along the route. The Panthay governor ‘bearing the title Tu-tu-du’ and a Chinese chief who had joined the cause visited the travellers.

They demanded either a list of the presents intended for Momien or permission to search our baggage, both of which requests Sladen stoutly refused, and referred them to Momien for instructions. In the course of the day it came out that reports had been circulated that our boxes contained live dragons and serpents and fearful explosives. The fears of the Tu-tu-du were quieted by a peep at some bottled snakes and frogs, and he begged us to pay him an official visit. This, he said, would strengthen his influence over the townspeople, whom he described as thieves and ruffians.

In Calcutta Anderson must have had a far quieter life. His obituarist for the Asiatic Society of Bengal, Alfred William Alcock CIE, FRS (1859-1933) of the Indian Medical Service and a successor at the museum, noted:

He will also be remembered as one of the earliest advocates of a Zoological Garden for Calcutta, and as one of the experts who greatly assisted in giving shape to that Institution when it was started.

The zoo is now known as Alipore Zoo.

Alcock also noted that much progress was made in the discovery and description of Indian animals during Anderson’s time there:

The time at which Dr. Anderson arrived in India was fortunate in another respect. It coincided with a great impulse given to Indian zoology by the publication of Jerdon's "Birds of India," the last volume of which appeared in 1864, and with the presence in Calcutta of a larger number of men interested in the study of the fauna than were assembled there at any time before or since. Amongst these men were Jerdon himself, Ferdinand Stoliczka, Francis Day, and Valentine Ball, all of whom have now passed away.

Probably at no time has so much progress been made in the study of Indian Vertebrata as in the years 1861-74, and in this work Dr. Anderson took an important part.

Between the two missions to Yunnan, John Anderson, aged 37, married Grace Scott Thoms (1834-1917) in Dundee on 8 December 1870.

John Anderson was elected as a Fellow of the Royal Society in 1879. After that he undertook his only other collecting expedition while based in India—to Tenasserim and the Mergui Archipelago in 1881-82. A multi-author, two-volume, account of the fauna was published in 1889. He also published a historical account of commercial and political interactions between British India and ports in Burma and Siam under the title English Intercourse with Siam in the Seventeenth Century. 

During home leave one can deduce from the address Anderson gave in the preface to books that he stayed in his home city of Edinburgh (he was elected as a Fellow of the Royal Society of Edinburgh in 1874). Number 6 Royal Terrace is now listed as part of a long terrace of town houses designed by William Playfair and built between 1823 and the early 1830s. However when he retired from India in 1886 aged 53 he settled in London after travelling in Japan with his wife.

In London Anderson was in poor health and he spent several winters in Egypt. He did not idle away his time, embarking on a study of mammals, reptiles and amphibians occurring there and in neighbouring countries. The first part was published in 1898; the second was completed after his death and published in 1902.

Anderson also began a collection of fish from the Nile and its tributaries after his death that work was continued with support from the Egyptian Government.

In London John Anderson lived at 71 Harrington Gardens, South Kensington. He continued zoological work and was well-known at meetings of the Royal Society, Royal Geographical Society and Linnean Society. He had been a fellow of the Zoological Society of London since 1869 and a vice-president for many years.

Ethnography was another of Anderson’s interests not just in terms of objects for the Calcutta museum. For example, in the Mergui Archipelago he studied what are now called the Moken and in Japan collected Ainu artefacts; that collection was given to the British Museum and the National Museum of Scotland in Edinburgh.

John Anderson died of cardiac failure after two days of pneumonia at the Old Hall Hotel, Buxton, a spa town in Derbyshire on 15 August 1900; he was 66. His sister from Edinburgh was present and she informed the local registrar. He left an estate of £13,767, 5s. 7d.—worth about £2 million in 2026. His wife died in London on 2 October 1917. They are buried together in Dean Cemetery in Edinburgh.

Alfred Alcock in his obituary summed up Anderson’s contributions:

Both in our Indian Empire and in North-Eastern Africa, Dr. Anderson contributed much to the solution of one the chief biological questions of the present day, an accurate knowledge of the distribution of animal life.

Anderson's Tombstone
Dean Cemetery, Edinburgh
Scotland, Burial Monument Inscriptions, 1507-2024

Dolphins, Rats and Captain Bowers

A substantial part of Anderson’s book on the zoology of the missions was taken up by a monograph on two cetacean genera. He compared the anatomy of the Irrawaddy Dolphin (Orcella brevirostris) with that of the very different in appearance Ganges River Dolphin (Platanista gangetica). He obtained a specimen of the former at the town of Bhoma, the highest navigable point of the Irrawaddy (now called the Ayeyarwady in Myanmar) on the first mission. He saw lots of the dolphins cavorting in the water but could not get his hands on a specimen since the fishermen ‘regard them with a superstitious respect, and each village is believed to be under the protection of a particular dolphin, which guards the fishery’. Not even the offer of 100 rupees worked.

…it was only by the fortunate acquisition of a dead carcass thrown upon the bank, and secured by Captain Bowers, that I was enabled to make a thorough comparison of the structure of this remarkable inhabitant of the river.

Captain Bowers was one of three delegates from the commercial community of Rangoon, in other words, the certain beneficiaries of increased trade to and from China along the Irrawaddy.

Irrawaddy Dolphin (Orcella brevirostris)

From Volume 2: Plates Anatomical and Zoological Researches: Comprising an Account
of the Zoological Results of the Two Expeditions to Western Yunnan in 1868 and 1975…

One of the species collected and described by Anderson was named for Bowers as Mus bowersi. The name has survived as Berylmys bowersi or Bowers’s White-toothed Rat.

 Berylmys bowersi. Bowers’s White-toothed Rat (current name)
From Volume 2: Plates Anatomical and Zoological Researches: Comprising an Account
of the Zoological Results of the Two Expeditions to Western Yunnan in 1868 and 1975…

Captain Alexander Bowers (born 1826, Greenock, Scotland; died 1887 Mergui, Burma) was a master mariner who produced his own report after the Sladen Mission. A copy of Bhamo Expedition. Report on the Practicability of Re-opening the Trade Route, between Burma and Western China, Rangoon, American Mission Press, 1869, sold at auction for £2,400 in 2026. However, Alexander Bowers  who died in 1887 has another but tragic place in history. His son, Henry Robertson ‘Birdie’ Bowers (born 1883) died with Captain Scott and Edward Wilson in the Antarctic. Both father and son have now appeared in these jottings independently (see HERE).

Anderson also named animals from the first mission for Sladen. I will cover Sladen and his eponymous rodents in another article.

Eponyms

In recognition of his work Anderson’s name was assigned to species described by others from the 1800s to 2018. In some cases his name has been used as part of the common name but not the scientific name. Particularly poignant is Anderson’s Gerbil, Gerbillus andersoni, named by William Edward de Winton (1856-1922) who completed the second volume on North African mammals after Anderson’s death.

Leffman D. 2025. A Murder in Yunnan: The Unsolved Killing of a British Diplomat on China's Southwestern Frontier. Hong Kong: Blacksmith Books. ISBN 978-988-76749-1-7. Available on Amazon HERE.

The now critically endangered Burmese Roofed Turtle (Batagur trivittata)
Once common and collected by Anderson at Bhamo

UPDATED: 6 July 2026

Terns: Hong Kong on board the Aberdeen to Po Toi Ferry

Birdwatchers in 1960s Hong Kong, in the words of my mother ‘would have looked at you gone out’ had you suggested that thirty years later a major site to see migratory birds was to be found in Hong Kong waters. It wasn’t until the late 1990s that the island of Po Toi was found to be a major stop-off point during the spring and autumn migrations. Since then ferryloads of birders have visited the island frequently in those seasons. Once off the ferry they only need walk a few yards to an old feng shui wood and surrounding scrub of the largely deserted village to see—on a good day—a host of birds. It helps that only a handful of people now live there, the main population having moved to Aberdeen on Hong Kong island, taking everything including the contents of most graves. Indeed it is very easy in the thick grassland to put more than one foot in am empty grave.

However, this post is not about Po Toi itself but a rocky islet lying between the island and Stanley peninsula on Hong Kong island—Castle Rock. Terns are regularly seen and try to breed there but disturbance by boaty types landing on the rock is, literally, a disturbing problem. The ferry. bringing hikers and those arriving to lunch in the restaurants by the shore, passes close to Castle Rock and terns may—or may not—be seen. AJP saw these Black-naped Terns (Sterna sumatrana) on the islet and over surrounding waters in early May but very little in the bird line once on Poi Toi.

Dr Brumback of the Eponymous Night Monkey: A Tragic End

‘Who was Brumback?’ was the question as we watched the family group of the eponymous night monkeys in the rewilded grounds of Rancho Camaná near Restropo in Colombia.

  Mother and baby (top right centre) Brumback's Night Monkey, Aotus.brumbacki Rancho Camaná, near Restrepo, Meta, Colombia. November 2026

In 1968, aged 19, Roger Alan Brumback was a first-year student at Pennsylvania State Medical College. He was looking for a research project. He talked with Dennis Staton in the anatomy department who had developed an interest in primatology and along with a former colleague had been developing chromosome analysis to investigate the phylogeny of monkeys. Nobody had looked at the chromosome complement (karyotype) of what was then believed to be just the one species of night monkey, then more widely called the owl Monkey. He bought some monkeys in the local town (!) (Hershey, Pennsylvania) and also visited Boston where he collected lots of blood and tissue samples from the zoo’s and a dealer’s stock. He then spent several years completing the work and in doing so realised that he appeared to be dealing with not one but two species. That work, together with a paper on the analysis of blood proteins which also showed a bimodal pattern, was published in the early 1970s. As such it provided the first clue that night monkeys were not a single species. By 1975 Brumback’s medical research life had moved away from the karyotpyes of monkeys and he gave all his material to Philip Hershkovitz of the Field Museum of Natural History in Chicago. In leaving the field through he also published a plea to other working of night monkeys to do the same.

At this stage it was a case of Brumback exits stage left.

Nearly thirty years later came Brumback’s discovery of his own discovery

In 2000 Brumback visited San Diego Zoo where he found himself looking at the night monkeys and at the label on their cage. He did not recognise the name Aotus nancymai but realised it must have been coined to honour Nancy Shui-Fong Ma, who had started work on the karyotype of primates at the time he was leaving the field. Intrigued by what he had seen Brumback looked up night monkeys and found as he scanned the list of species ‘Brumback’s Owl Monkey (Aotus brumbacki)’. He had no idea that Hershkovitz had worked on the taxonomy of night monkeys, including Brumback’s deposited specimens, and had published the revision in 1983. Hershkovitz confirmed the earlier suspicions and named one species Aotus brumbacki. Hershkovitz wrote: “The taxonomic revisions proposed by Brumback were not generally accepted. His urgent appeals to biological investigators for precise identifications of night monkeys they used in scientific research went largely unheeded”.

Brumback acted quickly to ‘provide a substantial donation’ to the American Society of Primatologists’ Conservation Fund aimed at the study and conservation of his eponymous night monkey.

Roger Brumback had made a name for himself in neurology and pathology, latterly in Alzheimer’s disease, moving to the Washington University School of Medicine in St. Louis in 1975, National Institutes of Health, University of Pittsburgh, University of North Dakota, University of Rochester and finally the University of Oklahoma’s medical college in 1986 where in 2000 he was David Ross Boyd Professor in the Department of Pathology.

The story does not end there. In 2013 Roger Brumback and his wife, Mary, were murdered at home by a former resident doctor on the pathology course, Anthony Garcia. Brumback, then chairman of his department, had been obliged to remove Garcia from his residency because of incompetence and erratic behaviour. In 2008 the man had been been dismissed from another pathology course in Omaha, Nebraska. A bit of smart policing suggested that the Brumback murders were linked to those of the son and housekeeper of the head of the course in Nebraska the day after Garcia was removed.  Anthony Joseph Garcia was found guilty of all four murders and sentenced to death. Appeals against conviction have been rejected and he remains on death row in Tecumseh, Nebraska. 

Roger and Mary Brumback in 2005

Roach ES, Bodensteiner JB. 2013. Obituary: Roger Alan Brumback, MD (1948-2013). Journal of Child Neurology 28, 703-705 DOI: 10.1177/0883073813493717

Wallis J. 2000. New species of owl monkey re-discovered…30 years later. American Society of Primatologists Newsletter 24 (2), 5.

Night Monkeys in Colombia

Grey-legged Night Monkeys, Aotus griseimembra
La Camelia, Victoria, Caldes, Colombia. November 2025

We saw three currently-recognised species of night monkey in Colombia last November. Night monkeys are variable in coloration and it is case of knowing what lives where in order to identify what one is seeing. The  three species are separated by high ranges of the Andes and major river systems, i.e. they are parapatric.

The first small group was seen by torchlight high in the trees on the track through the Otún Quimbaya Sanctuary on the western slope of the Cordillera Central. These were Lemurine Night Monkeys (Aotus lemurinus). A few days later were headed north west to cross the Cordillera Central and descend into the Magdalena Valley. Near the small town of Victoria we saw another species, the Grey-legged Night Monkey (Aotus griseimembra) by night. The next day in a coffee plantation we saw the same species by day. Two, the mother and father of the small group, were looking out of their tree hole. Then, after driving west to Bogota and on to emerge from the Cordillera Oriental we saw the third species, Brumback’s (Aotus.brumbacki) in the re-wilded grounds of Rancho Camaná, a popular lodge for wildlife trips. The small family group lives by day in a particular bamboo thicket. A new baby had arrived a few weeks earlier and could be seen being carried by the mother.

Mother and baby (top right centre) Brumback’s Night Monkey, Aotus.brumbacki
Rancho Camaná, near Restrepo, Meta, Colombia. November 2026

'Baby in the scope!'

Up until the 1970s there was only one species recognised. That was the Douroucouli, Aotus trivirgatus. Then, a series of discoveries showed that the number of chromosomes varied across their range across South and Central America from 46 to 58. How such changes in number came about and how they became fixed in a population has been the subject of much debate. The number of chromosomes—the karyotype—can have a number of different effects on hybrids between two forms, from  death at an early stage of development, to sterility (as in mules), to viability but gross chromosomal disturbance to, should say a split chromosome line up sufficiently well with the DNA of a single chromosome during fertilization, normal development.

These differences in karyotype together with differences in coloration of the neck and differences in susceptibility to malaria infection led Philip Hershkovitz (1909-1997) of the Field Museum of Natural History in Chicago, in a paper published in 1983, to split the douroucouli into nine species.

‘Owl monkey’ was used extensively as an alternative to douroucouli before and after the initial splitting of that species. I do not now when the use of ‘night monkey’ became to be accepted as the common name.

Research continues on the karyotypes and on the number of species, the latter complicated by adherents to particular ‘species concepts’. However, it does seem that the differences in karyotype have been generally accepted as constituting a barrier to reproduction and that differentiation by such means does result in ‘good’ biological species.

One of the reasons the karyotype of these monkeys has been investigated is that they are susceptible to Plasmodium falciparium, the parasite that causes malaria in the human population. Moreover, the time-course and pathological changes are the same. Therefore laboratory colonies of night monkeys have been established and have played a vital role in the development of antimalarials and to the development of vaccines. Those responsible for setting up and maintaining these colonies realised that karyotyping their stock was essential in  order to ensure that genetically compatible individuals were obtained and paired up. As far as I have read, the lab night monkeys are Grey-legged, A. griseimembra).

I have combined the geographical distributions for the three species shown in the IUCN Red Data List onto one map. The places we saw the animals are indicated by three red dots.

The night monkeys we saw by day were clearly looking back at us. However, their view of the world is very different from ours. Their eyes can see only in monochrome. The size of their eyes though shows their clear adaptation to life in the dark. By day, their pupils are tightly constricted.

I was particularly interested to see night monkeys by day. I have written before on the history of the discovery of Vitamin D and the particular requirement of South American monkeys for Vitamin D3 obtained either from the diet and/or by synthesis in the skin induced by the ultraviolet rays in sunlight. The question of course is how do the only nocturnal monkeys get their Vitamin D. As an experiment I asked a so-called AI agent the question. The answer came back that night monkeys must obtain their Vitamin D from their diet since they are nocturnal. Well that bit of AI sloppiness did not take into account of where and how night monkeys spend their day. At both the tree hole site, where bare areas of skin are exposed to sunlight, and in the bamboo thicket, where the tropical sun would have provided ultraviolet rays, there was clearly plenty of opportunity—up to 12 hours a day in fact—for synthesis of Vitamin D. In fact I can think of no other reason, other than early warning of approaching predators, for the tree-hole inhabitants to sit in full view. Indeed, depending on the size of the entrance hole a whole family group can be seen seemingly peering out at the outside day-lit world.

I will return to one of the species we saw in a future post since its description was an early and important event in the biology of night monkeys but one that left the man who did the work completely unaware of what had happened next…and the story ended in tragedy.