The largest land animal ever to have lived was surely a dinosaur, most likely a member of the aptly named titanosaur group. But what about the largest land mammal? It's hard to know for sure, partly because "largest" is a vague term that could be interpreted in different ways - do we mean weight or linear dimensions? But it's also just difficult to know when all you have to go on is the skeleton, and that's probably incomplete.
Sunday, 27 June 2021
Sunday, 20 June 2021
The first formal model of this concept in animal behaviour was described by Norwegian zoologist Thorleif Schjelderup-Ebbe in the 1920s. Having grown up on a farm, he had observed the behaviour of chickens, and, in his PhD dissertation in 1921, he described what is popularly known as the "pecking order". What happens is that, rather than fighting constantly, chickens establish a hierarchy where each animal knows where it stands. If two chickens face off against one another, the lower-ranking, or submissive, bird almost always backs down, allowing the higher-ranking, dominant bird to win without a proper fight.
Sunday, 13 June 2021
That third one was the barasingha (Rucervus duvaucelii). Fortunately, while I say 'used to be', I don't mean that it's extinct, as its closest relative, Schomburgk's deer is. Just that it's no longer common and widespread. It's primarily a grazing species, feeding in long grasslands and on forest edges and there used to be many of these on the Indian subcontinent. As recently as the 19th century, barasingha were found across almost the whole of central and northern India (aside, of course, from the Rajasthan desert) as well as in neighbouring parts of Pakistan, Bangladesh, and Nepal. They were especially common along the great floodplains of the Ganges and Indus Rivers.
Sunday, 6 June 2021
One thing we often see when animals that have been forcefully separated are reunited is that they interact even more than usual, rebounding after their isolation. For instance, male rats kept apart from their friends for a week greet one another with increased petting, social grooming, and anus-sniffing, compared with how they behave on normal days. It probably doesn't come as much of a surprise that something similar is known to be true of humans that have experienced temporary social isolation.