All the World's Antelopes: Giant Dwarfs and Zebra Stripes

Zebra duiker

When I was planning out this particular series, the duikers were considered to be divided into three genera. Firstly, there was the somewhat atypical bush duiker, which stood on its own, then the blue duikers and their closest relatives, and then... well, everything else. 

That "everything else" constituted the genus Cephalophus, named by Charles Hamilton Smith in 1827, and literally translating as "tufted head". This was, in turn, used by Edward Blyth in 1863 as the source of the scientific name for the duikers as a whole: the Cephalophinae. So it remained for over 150 years, on the basis that most duikers do look rather similar and there seemed little point dividing them up.

Then, in 2012, the genetic relationships between the various kinds of duikers were fully analysed for the first time. It turned out that the bush duiker was not so odd as it had appeared. It was adapted to a different habitat than every other species, yes, but, in evolutionary terms, it was just an offshoot lying within the more typical species. To truly represent how duikers were related, Cephalophus had to be divided. And, just a few months ago, that was formalised, with the American Society of Mammalogists splitting off three new genera from the original. (Of course, the ASM doesn't have the absolute final say on such things, but it's a major indicator of what taxonomists currently think, and is likely to percolate down to other sources over time.)

Shrinking Shrews

One of the challenges facing animals living in the world's temperate zones is how to survive winter, a time when food is often in short supply. Some deal with the issue by hibernating or migrating to warmer climes, and some invertebrates simply die off, leaving their eggs behind to hatch in the spring. The rest struggle through, something which can often lead to them losing body weight over the course of the season.

This is perhaps most obvious in animals that are naturally large to begin with. But, in 1938, German zoologist Georg Stein studied how winter affected the body weight of the smallest of mammals: shrews. He confirmed that they do, indeed, lose weight through the winter, despite already being unusually small. He was, in fact, impressed that they managed to survive at all, given how much food they normally require just to stay alive, their size requiring them to burn calories at a furious rate just to maintain their body temperature.

CSI Miocene: The Marks of Hyena Violence

Adcrocuta

Today, there are four species in the hyena family, one of which arguably isn't a hyena. However, not only does the family have a long history but, for most of that history, there were many more species than there are now. One estimate indicated that as many as 60 fossil species had been named as of 2008. We can be fairly confident that some - perhaps most - of those will eventually turn out to be the same species named twice, but there are also others that have been named since.

There is considerable variety among those species, as we might expect given over 20 million years of evolution. There are, for instance, at least three subfamilies, only one of which contains the three species we would consider "true" hyenas today. Even that subfamily includes animals that can be considered to have three basic lifestyles: bone-crackers, "running" hyenas, and those considered to be transitional.

All the World's Antelopes: Duikers of Bush and Forest

Common duiker

While the term "antelope" probably conjures up the image of something like a gazelle or a blackbuck, a great many species are much smaller than these animals. Often collectively referred to as "dwarf antelopes", they are scattered across the wider antelope family tree, belonging to several different groups. Being small and relatively inconspicuous helps when you're a herbivore, even if it isn't the only route to survival.

In terms of number of species, the duikers, technically referred to as the subfamily Cephalophinae, are one of the more successful groups of such small antelopes. The exact number of duiker species has fluctuated widely over the years, with some estimates reaching as high as 25. The latest version of the Mammal Diversity Database, however, lists 21, so that is what I am going with.

The Family Lives of Elephants

In 1961, Irven Buss published a scientific paper in which he proposed that the fundamental social unit among African elephants could best be described as a family group. While this put the subject on a firm scientific footing for the first time, he was hardly the first person to have noticed. Even white Europeans had at least mentioned the idea going back to the 19th century, particularly with regard to the Asian elephants living in the British Raj. 

Not to mention that the locals had surely noticed, and just not written scientific papers about it.

800th Synapsida

Some primates, to make up for a scarcity of posts...

This will be the 800th post to be posted in this blog. That means it is once again time for me to take a break from doing anything original and take a look back at the last couple of years or so. There have been some changes in how I've been doing things since the last of these updates, but they're relatively minor, and posting has generally been pretty regular.

The most common topic in the last 100 posts has been animal behaviour, which has overtaken the usual frontrunner of evolution. It's a broad topic, of course, and the exact ranking will come down to the variability of how I happen to label posts, but it shows that it's not all taxonomy and anatomical adaptations here. In particular, there have been several posts about sociability of late, partly due to the discussions of how different dolphin species associate into pods. There have also, as usual, been several posts on diet and habitat, both topics that inevitably come up a lot when I discuss particular living animals, or even the way that they have changed over millions of years. 

Eocene (Pt 6): Gophers, Camels, and Lady Gaga

Leptomeryx

World climate fluctuated during the Eocene epoch, but it was consistently warmer than it is today, including the lengthy Climatic Optimum, the hottest the world has been since the extinction of the non-avian dinosaurs. This naturally affected not just the weather, but where different types of vegetation were found. Much of North America was covered with subtropical forests, with at least some palm trees reaching as far north as Alaska, and temperate woodlands on the northern Canadian islands.

The animals you would have encountered in these woods would also have been unfamiliar, with most of the mammals not fitting within any family we would recognise today. Nonetheless, there were some exceptions.