Black-winged Cuckooshrike in Hong Kong

 This male Black-winged Cuckooshrike (Lalage melaschistos) posed for AJP in Hong Hong. A bird of south and southeast Asia it is classified as a scarce winter visitor and passage migrant in Hong Kong. However, we have seen at least one on our stay in and visits to Hong since the 1960s. There are early records of this species breeding in Hong Kong but that no longer seems to be the case. It preys on invertebrates.

Pygmy Marmosets in Colombia. The smallest monkeys in the world

Last November we saw these Pygmy Marmosets in Putomayo, a department in south-west Colombia. We flew to Villagarzon from Bogota, staying at the Portal del Sol, an ecolodge owned by a family rewilding the farmland which runs down to the river. And it was by the river that the troop of marmosets appeared. We had already seen the holes they had gnawed in the trees and which they visit to gather the material the tree has extruded.

The shape of their lower incisors is a clear adaptation to gnawing holes in trees. The exudate the marmosets eat is said to be mainly gum rather than sap and to comprise their main source of carbohydrates. Fruit, flowers, buds and nectar also feature in their diet. For protein they catch insects and other small invertebrates as well as small lizards which they search for in the vegetation.

Pygmy marmosets inhabit forests along rivers, spending a great deal of their time gnawing the holes in trees, exhausting it and then moving on.

Both troops had a couple of young. Only one female in the small troop breeds.

These Pygmy Marmosets were of the species originally named and when only one was recognised. Cebuella pygmaea. Those south of two large rivers were considered a subspecies. But the splitters rife in mammalian taxonomy who ignore the biological species concept erected it as a separate species. Cebuella niviventris. To confuse matters further the one we saw has two common names: Northern or Western Pygmy Marmoset as does the other: Southern or Eastern. Taken as a whole or, if you will have it that way, as the two species together Pygmy Marmosets occur in amazonian Brazil, Ecuador, Peru and Colombia. In Colombia it only occurs in the extreme south of the country.

Both groups we saw were low in the trees and made no attempt to flee. They did though carefully inspect us as we did them.

Holes gnaws in trees

Lots more monkeys from Colombia to come.

Edith Durham: from drawing Surinam Toads to Balkan anthropology and supporting Albania

In 1901, a book appeared which is still worth reading or simply for looking up what was known at the time. It is remarkable because the author was not known for his research on reptiles and amphibians but for birds in particular and vertebrates in general. He was Hans Gadow who was born in Prussia in 1855. After working with the big names in German zoology, he arrived in London to take a job at the Natural History Museum. From there he moved to Cambridge as Curator of Birds in the university’s zoology museum but after two years he was also appointed Lecturer in Vertebrate Morphology at which time he became a naturalised British subject. He was elected to the Royal Society in 1892 but the weird world of Cambridge only promoted him to a Readership in 1920, only eight years before he died.

Gadow's biographer for the Royal Society, David Meredith Seares Watson FRS (1886 –1973) palaeontologist and professor of zoology in University College London wrote:

…and he was greatly interested in the problems of animal colour and of geographical distribution.

In order to have first-hand knowledge of these matters, he travelled extensively in Spain and Mexico, observing amphibians, reptiles, and birds in their natural environments. The results are recorded in two books of travel, and in many papers.

In some ways, the best and certainly the most characteristic work which Gadow published was the volume on Amphibia and Reptiles in the ‘Cambridge Natural History.’ In this book, morphology holds a subordinate place, the greater part of it consisting of short and often most entertaining accounts of individual species regarded as animals living in the world.

It is full of observations of habits of all kinds—food preferences and the capture of food, locomotion, breeding habits, colour changes, the musical appreciation of Tortoises—many of them original, and most confirmed by his own observations of animals which he kept in his house outside Cambridge. Indeed, the whole book well displays the real love and understanding he had of these beasts.

The success of Gadow’s book which appeared in 1901 can also be attributed to the illustrations. Gadow in the preface explained: 

The drawings on wood were, with few exceptions, made by Miss M.E. Durham, mostly from living specimens—a procedure which has to a great extent determined the selection of the illustrations.

Why Edith Durham got the commission for illustrating Gadow’s book I do not know, other than, of course, her undoubted talent in drawing living animals that looked like living animals. Her father was a well-connected London surgeon. She was the first of nine children, a number of whom became well known in fields from science from suffragism.

A reminder that if you are reading this article other than on 'Zoology Jottings' it has been stolen from me.

Having used one of Miss Durham’s drawings of Tuataras to illustrate an article, I wondered what else she had produced and was surprised to discover that she had become famous in another field entirely.

Edith Durham

A great deal has been written on Mary Edith Durham (1863–1944) and what follows is a brief outline of her life. She was a student at Bedford College and then the Royal Society of Arts. Some of her works are held in galleries and museums. After her father’s death in 1895 she looked after her ailing mother. Utterly exhausted by this role her doctor advised a holiday. That advice taken she travelled by ship from Trieste to Kotor and then inland in Montenegro. That trip changed her life. She learnt Serbo-Croat on her return and delved into the history of the Balkans. After further extensive travel in the region she published her first book in 1904. Then she concentrated on Albania. Over twenty years she championed the Albanian people. The Balkans were a major cause of interest and indeed political obsession in Britain in the early decades of the 20th century. Edith Durham was known to be eccentric and ‘difficult’ getting up the noses of both London intellectuals and the Foreign Office for her advocacy of the people of Albania, particularly those who lived under dire conditions in the north of the country. She published her studies in anthropological journals and books; she was involved in aid organisations; she drew and painted the areas she studied, and she collected costumes, jewellery, textiles and artefacts. She was the first woman to be elected vice-president of the Royal Anthropological Institute.

Dubbed the ‘Queen of the Highlanders’ Edith Durham is still celebrated as a national heroine in Albania.

Why snakes lost a hormone. A ‘just so’ story or a ‘quite so’ story?

An interesting paper has appeared that shows that a gene present in most vertebrates is absent in snakes. The gene is responsible for the production of the unpronounceable peptide ghrelin. Discovered in 1999, ghrelin is produced by a number of organs in the body and has a multitude of actions, sometimes acting as a true hormone via circulation in the blood and sometimes, it would seem, locally on cells in close proximity. The main source of ghrelin is the lining of the stomach and a major target for its action is the brain.

There are a lots of hormones acting within the body that have an effect on such physiological processes as appetite, satiety, metabolism and gut motility. There is what is perhaps best described as a control network rather than simple cause and effect pathways. There is clearly a great deal of redundancy in the sense of safety-net measures, parallel signalling, cross-talk and feedback that ensure a chemical signal gets through to its intended target, enable effects to come into play in response to  changes in food intake, reproductive state etc, and for key variables, like blood glucose concentration to be regulated. One agent of this control network is Glucagon-like Peptide 1 (GLP-1), with which the obese and those who think they are obese are stuffing themselves, is one of those agents. Ghrelin is another. Ghrelin has been called the ‘hunger hormone’ because it promotes the desire to eat when injected. It also seems to have effects on the gut associated with food intake, on glucose metabolism as well as other functions in the brain like learning and memory. It also stimulates the storage of fat.

The authors of the paper pin the reason for the absence of ghrelin in snakes to their ability to go for very long periods without food. Although some snakes may lack that ability, the argument is still valid since the ancestors of snakes may have found selective advantage—or at least found no disadvantage from—a mutation that obliterated the ability to produce ghrelin. Thus it can be argued that all snakes, even those that can, do, or must, eat regularly inherited the condition from a common ancestor.

However, interpretation along those lines gets more complicated because the authors found the gene for ghrelin to be absent in the four species of chameleon examined and in two species of agama. In other words, the loss of ghrelin has happened independently at least three times in the snake-lizard lineage. The authors suggest that chameleons and the particular agamas (two species of Phrynocephalus) have similar lifestyles to the snakes as ‘sit-and-wait’ predators. That may be so but the chameleons do not sit and wait for that long, as anybody who has kept, bred  and reared chameleons knows. Therefore, I am not convinced that the loss of ghrelin in particular lizards is necessarily connected with the ability to go without food for long periods.

In a similar vein, members of other groups that go without food for long periods do not lack ghrelin, the crocodilians coming immediately to mind.

A reminder that if you are reading this article other than on ‘Zoology Jottings’ it has been stolen.

Defining with any degree of certainty what ghrelin does in mammals also seems problematic. Mice in which the gene for ghrelin has been knocked out seem to get along fine with only seemingly minor physiological changes, sometimes in unexpected ways. The general view seems to be that in terms of appetite control, for example, it is part of a signalling pathway with a great deal of redundancy.

Ascribing presumed function to biologically active substances found in extant animals to what may have happened in evolutionary history falls into the category of a ‘just-so story’ after Rudyard Kipling’s book of children’s stories including such gems as ‘How the leopard got its spots’. In living animals I have long railed against assumptions that biologically active substances found in milk have a particular or, indeed, any function in the infant, and have suggested the evidence that must be obtained to test each hypothetical function. When applied to evolutionary matters the task is even more difficult or impossible. Fossils, infuriatingly, are not amenable to experiment.

I would argue that it is a pity the authors of the paper on the absence of ghrelin in snakes have written their account almost as a test of the hypothesis that the phenomenon can be explained by the ability to go without food for long periods. Other just-so stories could be plausible: the short alimentary canal with long transit times for digesta, with all that implies for digestion, absorption of nutrients, and gut motility, could be another. Or was loss of ghrelin in their early evolution of no selective consequence to snakes and chameleons; in other words just neutral?

Studies in comparative molecular endocrinology are extremely valuable in stimulating the sort of questions that need to be answered in extant snakes. In short, is the rest of the control network similar to that of other vertebrates, minus grhelin, 

‘My conclusion on the  story at present: ‘Just so’ but not ‘quite so’.

Pinto RR, Ruivo R, Stiller J, Oliveira D, Castro LFC, da Fonseca RR. 2026. Ghrelin and MBOAT4 are lost in Serpentes. Open Biology. 16: 250162.

‘Sit-and-wait’ is the name of the game for these Common Boas (Boa constrictor)
on Cayos Grande, one of the islets of the Cayos Cochinos archipelago off
the Caribbean coast of Honduras. They lie on the branches waiting for a bird to
land within striking distance since there are no mammals on the island.
Our guess was that they were most likely to get the chance of a feed during
the migration of large numbers of birds from and to North America. In the shade
the boas are difficult for the untrained eye to spot. Once you eye is ‘in’ they are
easy to spot in the undergrowth behind the beach. Their coloration is distinctive
compared to those on the mainland and the pinkish hue gives rise to their local
name of ‘pink’ boa. And if you are staying for lunch the fish and chips are
excellent.