Zoology has a discipline: evolution; zoology is vertically integrated, concerned with biological organisation at the level of organisms in their environment, organs, tissues, cells and molecules. This blog meanders through the animal kingdom, from aardvarks and anoles, through mouse and man, to zorillas and zebras.
Showing posts with label Tibetan Plateau. Show all posts
Showing posts with label Tibetan Plateau. Show all posts
Tibetan Gazelles (Procapra picticaudata) inhabit the Tibetan Plateau of China, with just a few occurring in India. It was a species I was hoping to see and we did. Small herds appeared some distance away as dawn broke. Although we could see them clearly through binoculars, it was too dark for photography. Later, as we drove across the grassland, a single gazelle was by the road. Described by Brian Hodgson in 1846, the Tibetan Gazelle is now far less common than it once was owing to hunting and deterioration of its habitat caused by domestic livestock. It is classified as Near Threatened by IUCN. Another species (also first described by Hodgson) of the mountainsides that surround the Plateau is the Blue Sheep (Pseudois nayour) and it was here that we had our best view of them. A large flock feeding and resting on the steep grassy slope of an alpine meadow was behaving just as it says in the book. Classified of Least Concern by IUCN they are the favoured prey of Snow Leopards. Their range extends into Bhutan, Burma, Nepal, India, Pakistan and the Pamir Mountains of Tajikistan. These two species, as well as some other mammals and birds can be seen in my video taken over three days on the Plateau and ending with a heavy snow fall as we drove south from Ruoergai.
No sooner had we turned off the main road south of Ruoergai on the Tibetan Plateau in Sichuan and turned on the spotlights to scan the grasslands than a Chinese Mountain Cat was spotted by its eye shine. It was a good distance away but our track and its path were converging. Then the cat turned towards us as it hunted for rodents and I was able to take some video footage by torchlight. My camera was at the limit and the footage at these very low light levels is grainy but the salient features of this little-known cat that we could see through binoculars can just be discerned.
The late evening turned out to be one of those night-spotting classics that make spotlighting or lamping such a worthwhile experience. None of the mammals were close enough to be filmed but all could be seen through binoculars. After that Mountain Cat (Felis bieti) we saw another two plus Woolly Hares (Lepus oiostolus), a Red Fox (Vulpes vulpes), an Asian Badger (Meles leucurus), a Steppe Polecat (Mustela eversmannii) which was searching pika burrows for prey but then disappeared from view, and three Wolves (Canis lupus). The wolves were stopping, listening and then moving on to stop and listen again. Domestic yak herds are kept on the grasslands and it is hardly surprising that the yak herders have the enormous and fierce Tibetan Mastiff as guard dogs. The following night Tibetan Foxes (Vulpes ferrilata) abounded; we saw ten, as well as a Mountain Cat and a Red Fox. On a final night it was Red Foxes, six this time, a Mountain Cat and an Asian Badger. It was the density of the predators that surprised us, especially the numbers of Tibetan and Red Foxes in a relatively small area. The grasslands of the Tibetan Plateau are really productive in terms of producing large rodent and lagomorph populations which together with the odd dead yak must provide rich pickings for the carnivores. I will return to the Chinese Mountain Cat in a later post.
The Plateau or Black-lipped Pika, Ochotona curzoniae is an animal of, and confined to, the Tibetan Plateau. Ecologists have it marked as a keystone species of the Plateau where it is thought to increase plant growth by aerating and turning the soil through its burrowing. Many predators—like the Pallas’s Cat—rely on this species. Each family has a burrow with multiple entrances and a central nesting chamber. As we found last November on the Plateau in Sichuan, they are extremely common. We were surrounded by pikas, eating close to a burrow or dashing from one to another. Also extremely common was the White-rumped Snowfinch (Onychostruthus or Montifringilla taczanowskii). We noticed that in areas where these snowfinches settled, the pikas appeared from their burrows. Presence of the finches appeared to assure the pikas that there were no predators near. Snowfinches nest in old pika burrows. There was another species of snowfinch present in smaller numbers but formed into larger flocks, the Rufous-necked Snowfinch (Pyrgilauda or Montifingilla ruficollis). Pikas do not hibernate (unlike marmots which had disappeared for the winter). The do make stacks of hay, usually inside the burrow, which they obviously use to supplement their diet of live grasses and herbs, especially in winter. They also have a much thicker, lighter-coloured coat in winter. However, it appears that mortality during the winter is high, with only 1-2% of adults surviving to breed for two years. Pikas, like all lagomorphs, are coprophagic. They break down their vegetarian diet in the hindgut i.e. beyond the point that some of the nutrients produced can be absorbed. Two types of faecal pellet appear, the normal hard ones that litter the ground and special soft ones which they eat and send through the digestive tract again. A Plateau Pika eats a lot of grass—61 g/day and there are lots of Plateau Pikas. It has been estimated that in energy intake terms, about 6.2 million kilojoules per hectare are consumed each year by pikas in the alpine meadows of Qinghai-Tibet or 1.3 times that consumed by the domestic sheep kept there*. It is perhaps then not surprising that the Plateau Pika is regarded as an agricultural pest and that they have been, and are being, poisoned in vast numbers in order to protect the existing, and encourage the spread of, livestock industry in China. The damage caused to the grassland, to predator populations and, ultimately, to agricultural productivity itself can be imagined. We see vast areas of natural grassland infested by domestic yaks: the locals see agricultural land infested by pikas and rodents. But we can hardly complain; we have fields upon fields of rye-grass monoculture for our livestock. My video below shows a Plateau Pika that was filmed from the same position I used for the Pallas’s Cat (see my last post) at an altitude of over 3,500 metres.
*Zhang Z, Zhong W, Fan N. 2003. Rodent problems and management in the grasslands of China. In, Rats, mice and people: rodent biology and management, edited by Singleton GR, Hinds LA, Krebs CJ, Spratt DM. ACIAR Monograph No. 96, pp 316-319
Last November, we had a great morning of wildlife on the grasslands of the Tibetan Plateau north of Ruoergai in Sichuan. We arrived at the site (altitude 3,535 metres or 11, 300 feet) just before dawn. Almost immediately saw a Pallas’s Cat in the beam of the spotlight. However, it soon moved away. As light began to reveal the grassland we could see Plateau Pikas dashing in and out of their burrows. After short walk we looked over an area of marshland where there was a family of Black-necked Cranes (Grus nigricollis), the same species we had seen in Bhutan in 2016. The light was very poor but I managed to take a couple of still photographs at the extreme range of the zoom lens.
Black-necked Cranes
After walking back towards the car with pikas running and snowfinches flitting around us, two Pallas’s Cats were seen on a ridge. These cats are said to be solitary so we assumed that the two we saw together were a mother and her well-grown offspring. While some of the party tried to get nearer—and quickly becoming aware of the shortness of breath occasioned by rushing uphill at that altitude—but without frightening the cats, I set up a tripod and camera to take some video as one of the cats moved along the ridge line. Even with extra weighting gusts of wind moved the tripod slightly. These cats are only the size of a large domestic moggy and do not appear that big on the screen but you will be able to see their incredibly thick winter coat (which they shed in summer), the very flat face characteristic of the species and the low-set ears. Their slinky movement along the ground can only be described as like that of a miniature snow-leopard. So this video is like the dog that talked; remarkable for not that it talked well but that it talked at all.
Compared with other cats, the very short jaw has a set of premolar teeth missing. It is easy to see that these are ambush predators; nothing, not even their ears stand out from their outline. Pikas, their main prey on the plateau, must only be aware of them as they pounce. In Mongolia, their distribution is said to depend on adequate cover since the cats are preyed upon by wolves and foxes. Perhaps it is not surprising that the site we were visiting, which is well-known amongst the cognoscenti, has a couple of small quarries in which the cats can hide and in which one of ours was seen to disappear from view. They are animals of the steppes of Central Asia and have been recorded as high as 5,000 metres (these were at about 3,500 metres). Known as the Manul in Mongolia this cat was named Felis manul by Peter Paul Pallas (1741-1811) in 1776. Pallas was a Russian of German extraction employed by Catherine the Great as Professor of Natural History at the Academy of Sciences in St. Petersburg and to explore the geography and natural history of the outer regions of Russia. His expedition lasted from 1768 until 1774. Numerous mammals and birds are named after him. Another Russian explorer and naturalist, Nikolai Alekseevich Severtzov (1827–1885), moved Pallas’s Cat out of the genus Felis because it was so different from the rest of the species in that genus. He put it in a new genus Otocolobus, named from the Greek meaning ears cut short (i.e docked or maimed). For decades it was usually still referred to as Felis manul until 1907 when Pocock at the British museum upheld Severtzov’s classification. Molecular phylogenetic analysis indicates that it and an ancestor of the Leopard Cat (Prionailurus bengalensis), which we also saw on this trip at a lower altitude, diverged about 5.19 million years ago. Pallas’s Cat is classified as Near Threatened by IUCN. It was hunted widely for its fur but the main threats are habitat loss, predation from the dogs used to guard herds against wolves (the Tibetan mastiffs used to guard the herds of domestic Yaks are huge) and the poisoning of their pika prey to improve the pasture for those Yaks. Fortunately, these cats had not seen the recent BBC series Big Cats in which footage, claimed to be the first, of Pallas’s Cats in the wild was shown. There they were said to be highly elusive but ours were anything but. More video from that morning on the Tibetan Plateau soon.
