– An excerpt from T. C. Chamberlin‘s outgoing presidential address to the American Association for the Advancement of Science published one century ago today. Enjoy 2010.
Archive for December, 2009
Two of my favorite blogs struck a peculiar resonance today. Alex Wild has posted his favorite insect photos (plus a spider) of 2009. All of them are very good and some, such as Jan Zajc’s photo of mating damsel flies shown above, are nearly as spectacular as some of Alex’s own work. Meanwhile, BibliOdyssey has a selection of plates from August Johann Rösel von Rosenhof’s ‘Insecten-Belustigung’ (Insect Amusements) published serially from 1746 to 1761.
I can’t decide if I’m more impressesed with the amazing scenes captured by today’s best macro photographers or by the work of pre-photography nature artists like Rösel von Rosenhof who explored the same territory with paint, ink and paper. I suppose it is the insects that impress me the most.
Oh yeah, and “eustress” is a real word. Look it up.
The mainstream corporate science media is, to paraphrase Keith Olberman, going “cuckoo for coconut octopodes.” A new paper in Current Biology shows how the cephalopod Amphioctopus deliberately carries debris (shells, coconuts, garbage) for later use as building material to construct makeshift hideouts:
Many of the news stories about this paper imply, or state outright, that this marks the first observed case of “tool use” in an invertebrate. It’s not. In fact, it is not even the first purported case of tool use by an octopus.
Jones (1968) described an encounter with a weaponized Tremoctopus:
Among the frequent visitors to the submerged light were a number of immature female octopods, Tremoctopus violaceus. I dip-netted one of these from the water and lifted it by hand out of the net. I experienced sudden and severe pain and involuntarily threw the octopod back into the water. To determine the mechanism responsible for this sensation 10 or 12 small (40 to 72 mm total length) octopods were captured and I purposely placed each one on the tender areas of my hands. The severe pain occurred each time, but careful observation indicated that I was not being bitten by the octopod…Subsequent examination of one of these female octopods, 72 mm long, which had been preserved, revealed fragments of Physalia [n.b. the not-quite-a-real-jellyfish better known as the Portuguese Man O’war] tentacles attached in an orderly fashion to each row of suckers of each of its four dorsal arms. (Jones 1968).
Crustaceans are also known to employ stinging cnidarians (jellyfish, anemones and the lot) for defense, both by placing them on their body as a passive defense and by directly wielding them as weapons held in their appendages. Jones speculated that the octopus might use the Physalia tentacles to aid in prey capture as well as defense, but I’m not sure if that speculation has been confirmed by observation.
More reminiscent of the new Amphioctopus case is the report by Mather (1993) of careful selection of stones by Octopus vulgaris which were then carried back to an existing shelter and used to fortify the entrance. The line between construction behaviors (which are well known in many invertebrates) and “tool use” is blurry, but the Octopus vulgaris case seems to show the same kind of advance planning that is so striking in the coconut octopus shenanigans. Cephalopods are complex, intelligent even creative creatures and in retrospect these incidents are perhaps not all that surprising though no less impressive.
Another group of putative invertebrate tool users are more surprising from a cognitive standpoint. Compared to cephalopods, insects are pretty dumb at least one the individual level. However, ants are known to use tools in a variety of ways. Ants will drop small bits of debris (sticks, grains of sand) into liquid food sources then carry the soaked objects back to the nest. These makeshift vessels allow individual ants to increase their foraging efficiency by transporting larger volumes of food than they could carry in their crop alone. Ants are also known to drop small stones in their lairs of rival insects such as burrowing wasps as an apparent tactic to impede competition (Pierce 1985).
Again, if you know something about the astonishing behavioral repertoire of ants (e.g. domesticating aphids, constructing enormous underground fungus farms, building living bridges and rafts to cross bodies of water) these cases aren’t actually that surprising – but they do serve to highlight that depending on how you define it (which is a whole other kettle of fish I won’t go into here) “tool use” does not require as much cognitive complexity as one might expect.
Some other cases of purported arthropod tool use include “sand throwing” by ant lions, corpse camouflage by assassin bugs, and the construction of special sound amplification systems from leaves by singing katydids (Pierce 1985). Corolla spiders place stone rings around their lair. When a potential prey item bumps into the stones, the spider can sense the vibration and leap out to capture the prey (Henschel 1995). This is pretty clearly a modification of the prey capture strategies used by other ambush predator spiders that use systems of silken trip wires to detect prey.
You might quibble with any (or all) of these examples as representing the same sort of “tool use” as seen in Amphioctopus. But they do show a spectrum of specialized use of inanimate objects to further the biological goals of individuals and social aggregations. In the past, we often had to rely on somewhat unsatisfactory (though often enjoyable to read) written anecdotal accounts of behavior observed in the field. As the new paper shows, the ability to easily incorporate video in scientific communication–something that has only really taken off in the last few years–is fueling a much more sophisticated and well-documented record of animal behavior. To put it in a coconut-shell: the evolution of human technology is transforming our understanding of the evolution of animal technology.
Cool. Here’s a coconut octopus in a beer bottle, not really relevant, but too good to pass up.
Today’s Science features the description of a new Triassic non-Hellasaurian diapsid (erm “dinosaur” if you prefer), Tawa hallae. It is a remarkable animal represented by some really spectacular fossils, but there really isn’t much point in going into detail about it as the internet is already hemorrhaging with coverage and, as is the rule with celebrity fossils these days, dood’s already got his own multimedia enriched website (hosted by NSF…fancy). Oh yeah, I haven’t exactly read the entire paper yet either.
But let me dust off the old cultural studies head-dress and discuss something that I have mentioned before: the introgression of ‘non-western’ cultural traditions into paleontological nomenclature. The newly described dinosaur borrows its genus name from a Aboriginal American deity, Tawa, a Hopi sun god. Tawa is seen as the creator of the universe in Hopi mythology and makes the occasional appearance as gift shop merchandise or Marvel superhero.
Tawa is not the first fossil genus with a divine namesake. The protarded Azhdarchid pterosaur Quetzalcoatlus is perhaps the most familiar example, but recent years have given us Mahakala a dromaeosaur named for a Buddhist Dharmapala, and Beelzebufo an enormous extinct frog whose genus name might work out to something like “Philistine lord of the flies toad.” Nor is this actually a new phenomenon, the 19th century gave us Sivatherium and Mauisaurus, an extinct giraffe relative named for the Hindu lord of destruction/protection and a plesiosaur named for a semi-divine Polynesian folk hero respectively. CuriousTaxonomy.net has a fairly lengthy list of mythically derived scientific names for both extinct and extant organisms.
All of which raises the interesting question, how those who practice the religious traditions from which these names are drawn feel about all of this? I mean, I don’t imagine that many Ba’alists are that worried about Beelzebufo, and at any rate Ba’al has been disparaged a bit more directly over the last few millennia. On the other hand, Hopi religious ceremonies are still performed in the American Southwest. I’m not sure if the authors of the new Science paper consulted Hopi elders when deciding to name a dead dinosaur after a Hopi deity, it is quite possible that they did. Certainly I am aware of no established written (or even unspoken) ethical guidelines that cover such taxonomic practices.
Even for the blasphemous like me, there is no denying the mythic appeal of the American Southwest. I think it is quite possible to read the name as a respectful homage to the connection between the living and the ancient cultural and natural history of the region. Which is more of an honor, having a dinosaur named after one of your gods, or a comic book character?
Still, for a number of reasons, I can’t help but think that we won’t be seeing a ‘Muhammadosaurus‘ or ‘Yahwehia‘ any time soon.
For much more on Tawa (the dinosaur) check out this post on Chinleana including the emerging Q&A with one of the authors in the comments section.