Stories tagged creature spotlight

Aug
25
2009

4+ on the Schmidt Scale: Take that!
4+ on the Schmidt Scale: Take that!Courtesy Scott Camazine
Well, I understand that Science Buzz generally focuses on science in the news, as well as seasonal phenomena, and, frankly, this post doesn’t fall into either of those categories.

But yesterday I was starting to work on the next Object of the Month (I don’t want to spoil anything… but it’s “wasps’), and I came across an article on the tarantula hawk. The tarantula hawk is neither a hawk nor a tarantula—it’s a giant freakin’ wasp.

Growing up to 2 inches long, the tarantula hawk is one of the largest wasps in the world. It gets its name from its habit of paralyzing tarantulas, dragging the spiders back to their burrows (the wasps are that big), and then laying an egg on the tarantula’s living body. When the egg hatches, the wasp larva sucks the tarantula’s juices until it grows large enough to burrow into the hosts body. There it will eat the still-living spider’s organs, saving the vitals for last. When the wasp matures into an adult, it gives up its tarantula devouring ways, and lives off of fruit and nectar. How nice.

Anyway, the article also mentions that the tarantula hawk can have a stinger as long as 1/3rd of an inch, and that its sting is reported to be the second most painful sting in the world, according to the Schmidt sting pain index. (The Schmidt index was developed to the effects of insect venoms only, so I’m assuming that potentially fatal spider bites don’t count.) Naturally, the tarantula hawk’s position on the index begs the question, “What is the most painful sting?”

Answer: The bullet ant, so called because, supposedly, a sting from the bullet ant is like getting shot by a crossbow. I mean a gun. With bullets.

Native to central and South America, worker class bullet ants grow to about an inch, and are called “hormigas veinticuatro” by locals, or the “twenty-four [hour] ant” because the pain from a sting is supposed to remain unabated for a full day.

While the bullet ant will also bite, it delivers its sting the same way wasps and bees do, through a modified ovipositor on its abdomen (that’s all stingers are—egg-laying tubes evolved to inject venom).

The injected venom is a neurotoxin unique to the bullet ant: poneratoxin. A neurotoxin is a poison that affects the nervous system; poneratoxin interferes with the chemicals that allow nerve cells to send electrical signals to each other. So, when other insects and arthropods are stung with poneratoxin, they can be paralyzed (because, remember, you need nerves to control your muscles). When humans are stung with poneratoxin, they just experience extreme pain. Repeated stinging can lead to uncontrollable shaking, and temporary paralysis of the limbs.

But bullet ants aren’t generally aggressive, so how do we know about the affects of repeated stinging? Because some folks get themselves stung a lot. On purpose!

The Satere-Mawe people in Brazil use bullet ants as part of an adult-initiation tradition. (Or an initiation into adulthood. Whatever’s better.) Here:

Now, keep in mind, the tone of that video is pretty ridiculous. (That is, the “look at the weird stuff these weird people do” thing. We all do weird stuff, but other people’s weird stuff is just less familiar.) Also, if you go to the youtube page that video is hosted by, the description says that their hands “turn completely BLACK with poison.” That actually doesn’t make any sense, and it’s not true—the color is from charcoal.

Still, though… wild!

Oh, also, folks who have lived around the ants for a long time have used their stings to treat rheumatism (painful joints, etc), and have found that their bites are so strong that the ants’ mandibles can be used to pull the edges of a cut together, like stitches. The ant’s body is then twisted off, and the head (still biting) is left on the wound as a suture.

But we like the sting gloves. It’s news to me, right?

Sep
19
2008

The Ambulocetus: Not looking very fearsome at the moment, but it's thinking horrible, horrible thoughts.
The Ambulocetus: Not looking very fearsome at the moment, but it's thinking horrible, horrible thoughts.Courtesy ArthurWeasley
It’s Friday, y’all, and you know what that means!

No, not falling asleep at a booth in Applebee’s (should have gone to TGIF, right?)!

No, not a methadone suppository (not from me, anyway)!

And, no, not matching butterfly tattoos (that’s a Saturday thing)!

What’s left? Why a Science Buzz creature feature, of course! Sure, Friday has never been Creature Spotlight day before, sure, and, yes, it’s unlikely that I’ll remember to do it next Friday… But, hey, we’re Buzzketeers, right? We live in the now.

And so, with a small current science introduction, the creature of the week:

The crocowhale* (also known as ambulocetus, or “walking whale”).

If you’re keeping up on your cetacean evolution paleontology, you might have noticed this story recently. The ancestors of whales, paleontologists are quite certain, were land animals. Finding the evolutionary steps of their return to the water has been a challenge, however.

The distant ancestors of whales were carnivorous ungulates (ungulates are hoofed animals), that probably looked a little like dogs (with hooves). At some point these creatures began adapting to live and hunt in and around the water, eventually evolving into fully aquatic species.

Living vertebrates that swim employ a variety of propulsion methods. Several swimming styles seem to develop in sequence as a group of animals becomes more fully adapted to living in the water: swimming with four legs, paddling with just the back legs, undulation of the hips, undulation of the tale, and finally oscillation of the tail. The sequence of whale ancestor fossils seemed to follow this pattern (with modern whales having lost their hind legs to propel themselves with just their tails), except that for a long time it appeared that the step of swimming by hip undulation.

Recent fossil discoveries, however, show a whale ancestor that appeared to have a long fluke-less tail (it didn’t have big tail fins, like a modern whale), along with long hind legs and large, webbed feet. The skeleton seems to indicate that this creature would have propelled itself by undulating its hips, using its webbed hind feet as hydrofoils. And so, la de da, we have an important step in whale evolution in the bag. But, for the creature spotlight, we’re going back a couple branches in the cetacean family tree.

Before the group had evolved to the point of the hip wiggler above (called georgiacetus, by the way), there was the ambulocetus. Ambulocetus was a creature that probably still spent some of its time on land. It was about 10 feet long, and moved around on short, powerful legs. With its eyes and nostrils located on top of its long head, it probably looked something like a furry crocodile. Indeed, paleontologists think that ambulocetus probably acted very much like a crocodile, and filled a similar ecological niche.

Ambulocetus could have waited for large prey almost entirely submerged in shallow water, with only its eyes and nostrils breaking the surface. When something worthwhile came down to the water’s edge, it could have launched its body out of the water with its particularly powerful hind legs, ambushing its prey. The ambulocetus would have then dragged its struggling meal back into the water, and waited for it to drown. Yes! Crocowhale!

Here’s a cool illustration of ambulocetus in action.

* “Crocowhale” is a brand new term, and while I’m all for you using it in everyday life, don’t put it in any biology papers or anything. Yet.