In the previous post we looked at the biology and behaviour of vampire bats. This time we're going to take things a little bit further... Prior to the spread of people and domestic livestock, it is thought that vampires (here we're mostly talking about the Common vampire Desmodus rotundus) most likely fed on capybaras, tapirs, peccaries, deer and birds, though we also know that they sometimes feed on fruit bats and reptiles. Populations that live on islands off the Peruvian and Chilean coasts feed on seabirds and sealions. Now that the Americas are full of millions of cattle, horses,…
I am fascinated by bats, and I wish I knew more about them. And among the most fascinating of bats are one of the few groups that all people around the world have heard of: the vampires.... Various non-sanguivorous bats are regarded as vampires by various people in various parts of the world, but true vampires - the only truly sanguivorous bats and indeed only sanguivorous mammals - are unique to the American tropics. Though often classified in their own microbat family, Desmodontidae, it is universally agreed today that vampires are part of the American leaf-nosed bat family Phyllostomidae…
Watch this space. Full post to appear within next few hours. Keep these thoughts in mind; (1) vampire bats increase dramatically in numbers when megafauna (like modern livestock) are abundant; (2) there were lots more megafaunal elements in the Pleistocene than there are today. Hmm...
To begin with, let's get things straight and admit up front that Godzilla is not a real animal, nor was it ever. It's an unfeasibly big late-surviving dinosaur (belonging to the hypothetical taxon Godzillasaurus, according to some), mutated by radiation, with a radioactive heart, and virtually impervious to other gigantic monsters, robots, artillery, laser blasts, lava and fire. Not real. Sorry about that. But by posing questions about fictional entities we can still learn stuff, and you may be surprised to learn that Godzilla has, on occasion, been discussed semi-seriously by various…
Sorry: this is one of those annoying teaser posts that lots of people hate me for, but I wanted to post it in order to advertise what's coming next (I'd post it now if I could but I don't have the time). And I promise that the article is, within the context of this blog's theme, going to be relevant. Please check back soon. The vampire bats can wait a bit longer. And to those of you that know Godzilla, you'll know that he's done an awful lot of evolution within recent years (and I'm not talking about the 1998 TriStar Godzilla).
We didn't just go to the New Forest on Sunday to look at crossbills, fantastic and charismatic as they are. The main reason for the trip was the visit to Blackwater Arboretum: a locally renowned roosting site for.... Hawfinch Coccothraustes coccothraustes. The site is so renowned that, at this time of year, a large number of people turn up in the later afternoon to watch the birds come in to roost. A wooden carving that appears to depict a hawfinch (confusingly, the accompanying plaque tells you that the carving is named 'Fire crest' [sic]) can be found at the site, as you see from the…
I said I'd get distracted. Yesterday I again found myself in the New Forest in search of - can you guess - deer and birds. We saw deer alright, but mainly it was a finch-themed day ('we' = Southampton Natural History Society). As you can see from the adjacent photo, a lot of people were out, all hoping to see one particularly bizarre finch (that's me at the front, not a bizarre finch). But I'll come back to that later.... Our first sighting was of both male and female Common (= Red) crossbill Loxia curvirostra. They clambered around, feeding and calling, at the top of a pine, their…
Giraffine giraffes (that is, the giraffid clade that includes Giraffa and its closest relatives) are famous for being long necked, with the usual explanation for the neck being that it evolved to enable these animals to avoid competing with other browsers. But for this assumption to be experimentally supported you'd have to show that giraffes use their long necks to forage high up, and show that giraffes have a competitive advantage over shorter browsers. Surprisingly, it has been argued that these assumptions don't hold up. In some areas, over 50% of all giraffe browsing is done below 2 m…
So many of my so-called friends and associates are actually complete and utter *astards. First Matt Wedel goes and wins some coveted award for being a science genius. Now it turns out that Mark Witton and Graeme Elliott got to spend time with none other than Sir David Attenborough when at - cough cough - Buckingham Palace recently. I can only wince and shake my head in disgust. Mark's account of the sorry tale can be found here on his flickr site. Our academic parent and master, Dave Martill, is in India right now putting on the same display about pterosaurs that he did at Buckingham Palace…
Yet more musings on the evolution of blood-eating in passerine birds... So Redbilled oxpeckers (at least) are (sometimes) wound-feeding, blood-eating parasites (and before reading the following you need to see the previous posts here and here). If I were to indulge in one of those credibility-destroying rampant speculations about a possible future course of evolution, I might speculate that Redbilled oxpeckers are on their way to specialized and dedicated vampirism. At the moment they seem not to be in the habit of making their own wounds in order to feed, but it's not so far-fetched to…
In the latest installment in that 'evolution of vampires' thread, we learn how a chronic decline in populations of the Yellowbilled oxpecker has highlighted the pretty obvious fact that not all oxpeckers are alike. Why didn't I mention this sooner: d'oh! Before I got distracted by troodontids, owls, godwits, or sloths, I was talking about oxpeckers and the evolution of blood-feeding and vampirism. Here I'll start the beginning of the end of this thread: we'll go via blood-feeding passerines to bats, and then finish with pterosaurs. It's likely, of course, that I'll get distracted before I…
Sloths. Were there predatory sloths? Sloths that lived in the sea? Sloths that dug immense tunnels? Sloths on Antarctica? Sloths so keen to get to the US of A that they didn't wait for the land bridge, but swam the way instead? Well, let's see... Today I was asked a question about sloths. Sloths are among my favourite mammals, and hence I feel particularly guilty in not having blogged about them, though I did publish a review article on them fairly recently (Naish 2005). Not only does this distraction allow me to delay yet further those promised posts on blood-feeding birds and bats,…
It turns out that Cretaceous troodontid dinosaurs had asymmetrical ears. This makes them like owls, which also have asymmetrical ears. But not all owls have asymmetrical ears and, what's more, the story of ear asymmetry in owls is itself a pretty remarkable one.... Before getting distracted by godwits, I was talking about troodontids and their asymmetrical ears (and this itself came as a distraction, as beforehand I was talking about the evolution of blood-feeding in birds). The irresistible comparison that comes to mind is of course with owls, as owls also have asymmetrical ears (though…
My advice: get into the field and look at animals. Then wonder why some of them have curved bills, why they walk round in circles.. and whether a godwit is a big dowitcher or not. A while back I made an effort to stop writing so much about birds, and to concentrate instead on other tetrapod groups (to find out why go here). Alas, if you live in the temperate zone, birds are (after hominids) the most familiar and frequently encountered tetrapods, so I can forgive myself for writing the following. Don't worry if you were expecting more on asymmetrical ears, or on vampires: I will still return…
Apologies if you're here for the vampires. I'll come back to them soon, I promise, but in the meantime I got distracted... Some biologists - and scientists from other fields - have been quite critical of the fact that people speculate, and speculate, and speculate about dinosaurs (and by 'people' I don't necessarily mean palaeontologists, as in fact most technical palaeontological literature is appropriately dry, boring and conservative). But let's be fair: how can anyone not try to imagine what these animals were like when they were alive? I will also say that informed (note: informed)…
All of this yet to come... ... vampire finches.... .... vampire bats... ... more on vampire bats... ... and a remarkable interpretation of a group of pterosaurs. Sigh, if only there were more hours in the day. Also coming soon: Britain's lost tree frogs, Confessions of a part-time quadrupedal hominid, Gilbert White's pet tortoise, War rhinos, and more. I will be in the field this Saturday, in quest of bizarre finches. Watch this space.
More on oxpeckers, on wound-feeding, and on the delightful habit of eating earwax... In the previous post we looked at the behaviour of oxpeckers: the idea that they feed on blood and the other tissues of their hosts was introduced, and we can now doubt the idea that they are always symbiotic 'friends' of the mammals they clamber about on. As demonstrated by Paul Weeks in his several studies of the birds (Weeks 1999, 2000), oxpeckers spend a considerable amount of foraging time feeding - not on ticks - but on blood, ear wax, and on dead skin that they 'scissor' out of the fur. We also saw…
Welcome to Tetrapod Zoology ver 2: and we start with blood-eating birds.... To everyone who has come over from the blog's former home on blogspot, thanks for coming on over, and to new readers: welcome. This is a blog devoted entirely to discussion of the evolution, history, diversity, biology and behaviour of tetrapods, and for the two or three of you that don't know, a tetrapod is any vertebrate animal that possesses four limbs, or descends from an ancestor that had four limbs. Essentially it's amphibians, mammals and reptiles (the latter including birds), and the close fossil relatives…