The Case of the Missing Sengi

The rediscovery of a species of mammal thought "lost" for almost 50 years was a significant enough story this week to appear (briefly) on the front page of the BBC News website. I'm not sure how much further I can add to the BBC story in terms of detail, but perhaps I can put it into context, as well as providing it for those who may not have seen the original. So here goes.

To start with, what exactly is a sengi?

Sengis used to be (and often still are) called "elephant shrews". The term is falling out of favour because they aren't literally shrews, in the sense of belonging to the actual shrew family, although, as descriptive terms go, it's not a bad one. Since the late '90s most scientists, when they aren't using the more technical term "macroscelidean", instead use the Swahili name for the animal, which is also the one I'll stick with.

New Mammal Species 2016

Reticulated giraffes

2016 has, on the whole, been a bit of a rubbish year. Or so the common wisdom has it; one suspects that, for instance, the deaths of some particularly prominent celebrities at the beginning of the year has heightened our perception of those that died later on (relative to any other given year). And it's probably been quite a good year for you if happen to be a Trump supporter, or a fan of Nigel Farage.

But that debate doesn't belong here, instead, as the year draws to a close, it's time to take a survey of the species of mammal that have been newly discovered this year. Or, more accurately, newly named, since what we generally do these days is find some population of a previously known species that turns out not to belong to it, and to be something else instead. There have, as always, been a fair number of them this year, and there's no guarantee that they'll all stand the test of time, and still be considered valid species in, say, 2026.

My survey is, therefore, inevitably biased, with a just a semi-random sample of some of the species announcements I happen to have come across. Most of them are going to be small animals, since they're easier to overlook in the first place, but there are a couple of quite large ones. And, by "large", I don't mean just "wolf-sized", either.

New Mammal Species 2015

Brown titi monkey

As 2015 draws to a close, it's time to look at some of the species of mammal that we didn't even know existed this time last year. Of course, the reality is that, in most cases, we knew that the animals existed, we just didn't realise that they were a species. Some we thought were subspecies, and we now have enough information to promote to full species status, while others we just hadn't noticed were different at all.

Telling the difference between a subspecies and a species is a difficult, and rather subjective, art. It essentially relies on you being able to demonstrate that the animals don't usually interbreed in the wild when they get the chance. Not that they can't. Not that they don't sometimes. Just that they don't usually. You can really only do this by showing that their genetics are distinct, and even doing that may depend on how good your sample is. As a result, while new species of mammal are named every year, it's worth noting that this isn't a one-way process... it's not that unusual to demote a species back down to subspecies as more information comes in.

New Mammal Species 2014

Waiomys mamasae

New species of animal are discovered every day. That isn't hyperbole; I mean it literally. I'm not sure of the exact number of new species that were named last year, but it's in the thousands, and likely a five-figure number, at that. This is, you'll note, rather a lot.

The great majority, of course, are insects. "An inordinate fondness for beetles" and all that. Most of the ones that aren't are also invertebrates, typically small things like mites, spiders, or crustaceans. When we do look at vertebrates, most of the new ones are fish, with amphibians and reptiles not far behind. For instance, looking at the new species described in the daily journal Zootaxa (by no means the only source for such things, although it is one of the largest) on Friday 12th December 2014, I count seven beetles, two flies, three crickets, a frog, a salamander, a gecko, and (unusually) a bunting.

In fact, new birds are, if anything, even more rarely described than new mammals. But while while new mammal species are not discovered that often, there are still several each year. So, for this, the last post of 2014, why not look back at some of the mammals that were officially described for the first time this year? This will not be, by any means, a comprehensive survey, just a sampling, and I'm not even counting the various new fossils that have been described, but nonetheless, here we go:

A New Kind of River Dolphin?

Amazonian botos (probably)

I could, perhaps, have titled this post "I Told You So".

Back in August, at the end of my post on the newly discovered olinguito, I said: "Should we expect more new species of mammal to be found, perhaps even large and interesting ones? You can count on it." I also suggested in that post that remote jungles were exactly the sort of place you'd expect to find one. Well, since I wrote that, we have discovered at least one, and possibly two, new species of large mammal that fit exactly that description.

The first was the kaboman tapir (Tapirus kabomani), which lives in the Amazon jungle, and which was described a couple of months ago. I'll refer you to Darren Naish's blog if you want to know about that, since I have nothing useful to add to what he's already said. There is, so far as I can tell, no dispute or argument about the reality of this tapir as a new species - the first new tapir to be described since 1865. The acceptance of other one, published just last week in the online journal PLoS One, appears to not quite be so clear cut.

The animal in question is a new species of river dolphin, and it, too, was discovered in the Amazon jungle. But, before we look at the details, it's probably best if I start by describing what a river dolphin actually is.

Dolphins, on the whole, live in the sea; this is surely not a great surprise. Yes, they sometimes travel a short way up particularly large rivers, and some of them even do it on purpose. But, generally, the sea is where you expect to find them. Now, there is an exception, and I discussed it back in 2012: it's the tucuxi (Sotalia fluviatilis). This spends its entire life in freshwater, and, as I said at the time, it's the only true dolphin that does this.

Welcome, the Olinguito

If you follow any sort of science news site, especially if you read the zoology bits, you cannot have failed to notice the recent announcement of the discovery of a "new species of carnivore" in South America. By the standards of such things, its a major news story - the last time this happened in the New World was in 1978, when the Colombian weasel was discovered. In addition to the news coverage, the original announcement is available to read (all 83 pages of it), free online, for anyone who cares to. There's probably not a lot I can add to all that.

Still, I feel that it's not something I should really ignore, so here's my take on it, and an attempt to put the discovery into some sort of context.

Let's start with the obvious: what is this new animal, exactly? The olinguito (Bassaricyon neblina) is a newly described species of olingo. Which may, in many people's minds, raise the question: "um... what's an olingo?"

Olingos are long-tailed, tree-dwelling, members of the raccoon family, found in the jungles of Central and South America. They were first scientifically described, as a group, by the American zoologist J.A. Allen in 1876, which is itself remarkably late (all the other main groups within the family had been discovered by 1830, and most of them well before that). They've never been seen to eat anything but fruit and flowers, although it's suspected that they also snack on the occasional passing insect.

News in Brief #8

Attack of the Killer Walrus (Or Not)

The two principal families of fully aquatic carnivoran are the seals and the sea lions. To the casual observer, they can most easily be distinguished by the shape of their hind limbs. Sea lions can walk on all fours (albeit with a comical waddle), while true seals have to drag themselves about on land, their hind flippers being of little use out of the water. It's this that tells us that fur seals, for example, are members of the sea lion family, and not 'true' seals. But seals and sea lions are not the only aquatic carnivorans: there are two others. Firstly, there's the sea otter, a member of the weasel family. And then there is the walrus.

Walruses are kind of weird, when you think about it. Although they're probably more closely related to sea lions than they are to true seals, they're actually neither, and the walrus family is one of those odd mammal "families" that has only one species in it. But, as is so often the case with such "monotypic " families, that's only true if you count the living species. Because there used to be more.

Part of the reason that the walrus is so obviously peculiar is that it's adapted to doing only one thing (eating shellfish) and, moreover, doing it in a fairly specific habitat. But not all prehistoric walruses were the same. Some, for example, used to live in subtropical waters, and by no means all of them fed on shellfish.

News in Brief #7

Geoffroy's spider monkey

Monkey Sleep, Monkey Poo

Poo is useful stuff to zoologists: a lot of field work involves examining the stuff. It can tell you what an animal has been eating, how it behaves, and maybe something about it's genetics. And, of course, it can also tell you where it's been. Take Geoffroy's spider monkey (Ateles geoffroyi), for example.

Spider monkeys are moderately sized monkeys, noted for their prehensile tails and remarkable agility. I saw some (although not Geoffroy's species) at London Zoo on Monday, and, despite the poor weather, they really were a delight to watch, full of enthusiasm and energy. Seeing them at play, it's hard to escape the impression that they have five arms: their feet are effectively an extra pair of hands, and their tail is so flexible and has such a good grip that it might as well be a fifth one.

They live, unsurprisingly enough, up in the trees - specifically ones in Central America - sleeping in them at night and travelling between them to feed during the day. They have particular favoured trees to sleep in, and deposit a lot of dung at the base over the course of the night. Such 'latrine' use is common among many mammals, and just finding where they are provides a good means of establishing what the monkeys are up to without having to disturb them.

News in Brief #6

Japanese macaques

Baby Monkeys are Cute

For we humans, it's fairly easy to estimate how old another human is just by looking at them. It may not work perfectly, but we can instinctively assign someone to at least to a broad age class - young adult, middle-aged, and so on. There are plenty of clues to help us to do this, and it's a useful ability for shaping our interactions with one another, so it's not too surprising that other social animals can do the same thing. Perhaps one of the more striking examples is our reaction to the faces of our young.

Very young humans have a constellation of features that highlight their age: rounded face, large eyes in comparison to the face, and so on. The same set of features are found in other baby mammals, and were described by the great behavioural biologist Konrad Lorenz as "kindenschema". Perhaps a more everyday term for the same phenomenon is "cuteness". Cuteness triggers positive, maternal and protective reactions in humans, and its by no means restricted to our own species. Kittens and puppy dogs are undeniably also "cute" to the vast majority of humans and its for the same reasons. We can see the same phenomenon in the looks of toys such as teddy bears, the kawaii appearance of characters in Japanese cartoons, and so on.

Discovery of the World's Newest Monkey

Hamlyn's monkey (left) and lesula (right)

Even today, new species of mammal are being discovered all the time. The majority are small animals, often nocturnal, or otherwise difficult to find. Just in the last few months I've seen the announcement of four new bats and a mole, and that's without me particularly trying - there may well be more discoveries I haven't seen. In many cases - as happened with the bats, for example - it's not that the animal had never been seen before, it's just that it wasn't obviously a different species. Until you look closely, one mole may look much like another.

The discovery of larger species is a rarer event. Which is why the announcement of an entirely new species of monkey is so exciting. This new animal, the lesula (Cercopithecus lomamiensis), is the first new species of African monkey to be discovered since the critically endangered kipunji in 2004, and only the second since 1984.

News in Brief #4

A Rat's Idea of 'Vermin'

Arguably the most important factor in the success of humanity as a species is out ability to modify the environment around us, to take somewhere inhospitable, and not only make it habitable for our species, but enable it to support far more humans than any natural environment possibly could. The existence of cities, and of the great swathes of agricultural land around them are clear testaments to modify the world to the point of creating entirely new environments.

We may be the most spectacular example of a species that can do that, but many others do so, albeit on a smaller scale. They're not all mammals, or even vertebrates - consider termite mounds, of example. Often, the way that one species modifies it environment also helps others, whether intentionally, as in humans providing farmland for cattle, or as an unavoidable by-product, such as humans creating the perfect habitat for rats. This process is called "facilitation", and it seems to have been more studied in botany than it has in zoology.

However, Andrew Edelman, of the University of New Mexico, has been looking at the interaction between two animal species in the Chihuahuan Desert. Banner-tailed kangaroo rats (Dipodomys spectabilis) are, like many rodents, seed-eating herbivores. They make large mounds in the desert in which to live, and, while they're generally pretty anti-social, not letting other rats near their homes during their lifetime, the mounds can nonetheless be passed down from rat to rat for generations, sometimes surviving for over fifty years.

News in Brief #2

Columbian ground squirrel

The Wooing Ways of Ground Squirrels

Male animals will go a long way to ensure that they become the father for a female's young. If the female isn't likely to be monogamous, they may chase off rivals, beat them up, display their masculinity, or just have giant gonads. But male Columbian ground squirrels (Urocitellus columbianus), it seems, like to try a bit of smooching.

Columbian ground squirrels (that's British Columbia, by the way, not Colombia in South America) live in complex, underground burrows. They mate in the early spring, after waking up from hibernation, and the females are sexually fertile for just one day during each year, making competition between males particularly important. Yes, the males do fight one another to establish territories, but, according to a new discovery, that isn't their only trick.

In short, they don't go too far on a first date. They sneak into the female's burrows at night, when she isn't sexually fertile, and spend the night with her, without doing anything. The next morning - and the more experienced males do seem to be pretty good at predicting in advance the one day when this is going to happen - the females wakes up feeling randy... and, well, who's already there?

News in Brief #1

Sometimes weeks go by and I have difficulty finding anything very new to post, at least that isn't too similar to something else I've already done recently. Just as often, though, I have to pick between a number of possible stories, and some end up being pushed to the back of the queue, and never leave it. So, every couple of months or so, I'm going to gather up stories that didn't quite make it, and post a short summary here. So, without any more ado:

Are Foreign Mating Calls Still Sexy?

Sika deer

Mating calls are hardly an unusual feature in mammals, and deer are no exception, especially where the males like to gather a larger number of females around them to mate with. You'd think that part of the point of a mating call is to attract females of your own species, so that you end up with a suitable partner. A group of British, Austrian, and French scientists recently tested this out with female red deer (this is the European version of the animal Americans call an 'elk'). They put up loudspeakers emitting recordings of male red deer, and of male sika deer, a closely related Japanese species with similar mating habits, but that looks quite different.

Sure enough, most of the females wandered over to where the calls of the male red deer seemed to be coming from. But ten percent of the females actually seemed to prefer the calls of the sika males, apparently finding them more enticing than the ones from their own males. The researchers say that this may lead to "permeability of pre-zygotic reproductive barriers"... by which they mean a willingness to have sex with the wrong species. And, indeed, after sika deer were introduced into parks in Europe, some hybrids between the two have been reported. Some red deer does, it seems, just find the exotic attractive.

The Insightful Elephant
We've known for a while that we aren't the only species to use tools, even if we ignore instinctive use of objects - such as birds smashing open snails on rocks. Chimpanzees, for example, have the intelligence to work out how to use simple tools to acquire food, and, outside the world of mammals, even some species of crow have been shown to do the same. Elephants seem a reasonable candidate for another animal that might do the same. They are intelligent animals, and they have a trunk that can pick up and manipulate objects.

A New Species of Dolphin

Common bottlenose dolphin

On September 14th, the discovery a new species of dolphin, the burrunan dolphin (Tursiops australis) was officially announced. There has already been a fair bit of coverage of this in the media (see, for example, the BBC story), but I want to focus here on how this all came about. How exactly do you go about naming a new species?

In theory, it's a fairly straightforward, if somewhat laborious, process. You find your new species, write up a description of what it looks like, and how to tell it apart from similar species, designate a holotype (more on this later), think up a name, and get it published. Leaving aside the difficulty of the first part of that - "first, find your new species" - that's often all there is to it. But, with dolphins, the story has been rather more complicated than that.

First, let's get our bearings. The sort of dolphin we're talking about here is a bottlenose dolphin, a particularly well known type, and commonly seen in sea mammal parks, where they have been trained to perform a number of tricks. They live in every ocean, avoiding only the very coldest of polar seas and are therefore extremely widespread.