Monday Science Links

This week's yummy science:

• Brian at Laelaps wonders how saber-toothed cats used their teeth: The feeding habits of saber-toothed cats have long perplexed scientists. How in the world did these cats kill prey with their almost comically-oversized teeth? Did Smilodon and its kin use their teeth like daggers to stab prey to death, or did they simply rip out a huge chunk of flesh from the side of a victim, leaving their prey to hemorrhage to death? While the stabbing hypothesis has generally been abandoned it is still a mystery how sabercats used their immense canines, especially since there were three different types of saber-toothed cats which differed in their killing techniques. Perhaps the characteristics of the prey animals themselves could provide some clues as to how the felids might have fed. There may be more than one way to attack a mammoth or giant sloth, but some ways would certainly have been better than others.


• A twofer! Ed at Not Exactly Rocket Science posts on songbirds that eat bats, and Darren at Tetrapod Zoology is beaten to it, but still posts. Ed: When food is precious, animals can resort to strange behaviours in order to satisfy their hunger. Take the great tit. Its usual diet of insects and creepy-crawlies is harder to come by in winter. But in one Hungarian cave, great tits, ever the opportunists, have learned to exploit a rich and unusual source of food. They kill sleeping bats. and Darren: Various predatory microbats around the world predate on small birds, but it was a bit of a surprise to learn that this behaviour occurred in western Europe. Of course, bats don't have it all their own way: it's well known that bats are heavily predated upon by raptors and owls. As revealed today by Péter Estók and colleagues in Biology Letters, however, it now seems that hibernating pipistrelle bats have another predator to worry about: the Great tit Parus major. Say what? For those non-Eurasians who may not be familiar with this species, it's a very widespread and distinctive tit (or titmouse, if you must), easily identifiable thanks to its black head, striking white cheeks and black belly stripe.


• Okay, this, too, is about those bat-eating tits. But bec of Save Your Breath for Running Ponies has a very different take on it: Okay, yes, Pipistrelle Bat, this situation is all very gross and dire for you. No one is particularly happy about having to wake up from an enormous sleep, especially when there’s a chance they’re going to have their brain case pecked open when they do so. But it doesn’t have to be this way. You need to fight back, and playing to your strengths is probably the key to your success in this situation. But what are your strengths, tiny Pipistrelle, I hear you ask? Well, being bats, preferring to hang out in dark caves as you do, tightly hugging yourselves with those membranous black wings as you grip inside leaky crevices with those dirty, possibly frayed claws of yours, you’ve been described on more than one occasion as being “creepy.” But don’t be offended, Pipistrelle Bat, I’d still invite you for tea at my house, so long as you promised to keep the chatter to a minimum, but more to the point – your creepiness could be your best asset in driving away those great tits.


• Carl Zimmer, who keeps The Loom, has a piece in Time this week on canine cognition: Henry could find the biscuit by sniffing the cups or knocking them over. But Hare does not plan to let him have it so easy. Instead, he simply points at the cup on the right. Henry looks at Hare's hand and follows the pointed finger. Kivell then releases the leash, and Henry walks over to the cup that Hare is pointing to. Hare lifts it to reveal the biscuit reward. Henry the schnoodle just did a remarkable thing. Understanding a pointed finger may seem easy, but consider this: while humans and canines can do it naturally, no other known species in the animal kingdom can. Consider too all the mental work that goes into figuring out what a pointed finger means: paying close attention to a person, recognizing that a gesture reflects a thought, that another animal can even have a thought. Henry, as Kivell affectionately admits, may not be "the sharpest knife in the drawer," but compared to other animals, he's a true scholar. It's no coincidence that the two species that pass Hare's pointing test also share a profound cross-species bond.


• Emily Lakdawalla at the Planetary Society blogs on Earth crossing the ring plane: Since Saturn's equinox on August 11, Earth has been in an unusual position, on the night side of Saturn's rings. Today, though, we move back to the sunlit side as Earth crosses through Saturn's ring plane. This would be an interesting time to take photos of Saturn except for one small problem: Saturn's almost at solar conjunction (that event happens on the 17th), so it's way too close to the Sun for photography right now. I wrote much more about this for today's episode of 365 Days of Astronomy; I'll post the transcript of that show below. One of the things I discuss in this show is "mutual events," when an observer manages to catch a view of one body in space passing across another. Here are a bunch of nifty animations of mutual events captured by Cassini over the past few years...

Enjoy!