Tag: poison

Coin-sized frog becomes mite-y thanks to poisonous diet

By Ed Yong | November 4, 2010 9:00 am

Monte_Iberia_eleuthMiguel Vences was dissecting a frog no bigger than his fingernail when he smelled an unusual acrid smell. “Maybe it can be compared with vinegar,” he says. “It is a totally different smell, but somehow the same kind of bitter-burning feeling when you get it into your nose.” He remembered the distinctive scent from his experiences with other species of frogs, all of which have powerful poisons in their skins. He reasoned that the species he was cutting open – a beautiful Monte Iberia eleuth – was similarly armed with toxins. A chemical analysis of its skin confirmed Rodriguez’s suspicion. The frog’s skin was laced with toxins, including a group of muscle-paralysing poisons called pumiliotoxins that are common among poison dart frogs.

Read More

Groovy teeth, but was Sinornithosaurus a venomous dinosaur?

By Ed Yong | December 21, 2009 3:00 pm

It’s a dinosaur tooth, and clearly one that belonged to a predator – sharp and backwards-pointing. But this particularly tooth, belonging to a small raptor called Sinornithosaurus, has a special feature that’s courting a lot controversy. It has a thin groove running down its length, from the root to the very tip. According to a new paper from Enpu Gong of the Chinese Academy of Sciences, it was a channel for venom.

Thanks to a certain film that shall remain nameless, a lot of people probably think that we already know that some dinosaurs are venomous. But the idea that Dilophosaurus was armed with poison, much less spat its toxins at its prey, is non-existent. Some scientists had speculated that they were venomous based on their bizarrely notched and allegedly weak jaws. But these notches have since been found in many other species and no one has ever actually measured the strength of Dilophosaurus‘s jaws.

The best sign that a dinosaur was venomous would be the presence of grooved or hollow teeth. With some notable exceptions, most animals with poison bites use grooves like these to channel their toxins from glands in their mouth to whatever they bite. And grooves are exactly what Gong and his colleagues found in Sinornithosaurus‘s well-preserved skull. Bryan Fry, who discovered venom glands in Komodo dragons earlier this year, says, “It is an absolutely fantastic piece of work. I actually got goose-bumps reading it! Other studies have suggested dinosaurs may be venomous but this is the most solid piece of evidence.”

Sinornithosaurus (meaning “Chinese bird-lizard”) is a small feathered dromaeosaurid (or, more commonly, ‘raptor’) and an early distant cousin of the birds. Its teeth are unusually large and Gong says that those in the upper jaw are “so long and fang-like that the animal appears to be saber-toothed”. They’re very similar to the fangs of back-fanged snakes like boomslangs and vine snakes.

Gong says that other aspects of the skull in support of his venom hypothesis. His team noticed that Sinornithosaurus has a small hollow on the side of its jawbone that could have housed a venom gland. They also found a thin groove running along the animal’s jaw, with small pits at the top of each tooth. They interpret this canal as a “collecting duct” that channelled venom from the gland to the teeth, and each pit could have acted as small, local venom reservoirs. David Burnham, a co-author on the paper, says, “Other fossil animals (dinosaurs, lizards, mammals) have been suggested to be venomous simply on the presence grooved teeth but out work found multiple lines of evidence.”

Read More

Immune snakes outrun toxic newts in evolutionary arms races

By Ed Yong | March 10, 2008 8:07 pm

Blogging on Peer-Reviewed Research

The story of evolution is filled with antagonists, be they predators and prey, hosts and parasites, or males and females. These conflicts of interest provide the fuel for ‘evolutionary arms races’ – cycles of adaptation and counter-adaptation where any advantage gained by one side is rapidly neutralised by a counter-measure from the other. As the Red Queen of Lewis Carroll’s Through the Looking Glass said to Alice, “It takes all the running you can do, to keep in the same place.”

Garter-snake-and-newt.jpg

The Red Queen analogy paints a picture of natural foes, wielding perfectly balanced armaments and caught in a perpetual stalemate. But this is an oversimplified view. It is entirely possible for one combatant to develop such a significant advantage that it completely outruns the other and temporarily wins the race.

Charles Hanifin from Utah State University has found one such example among garter snakes and newts living along North America’s west coast. Even though some of the newts pack one of the most powerful poisons used by any animal, they still fall prey to garter snakes that have evolved extreme levels of resistance to them.  In some locations, the snakes’ immunity is so complete that the not a single newt is poisonous enough to overwhelm them.

Read More

NEW ON DISCOVER
OPEN
CITIZEN SCIENCE
ADVERTISEMENT

Discover's Newsletter

Sign up to get the latest science news delivered weekly right to your inbox!

Not Exactly Rocket Science

Dive into the awe-inspiring, beautiful and quirky world of science news with award-winning writer Ed Yong. No previous experience required.
ADVERTISEMENT

See More

ADVERTISEMENT
Collapse bottom bar
+

Login to your Account

X
E-mail address:
Password:
Remember me
Forgot your password?
No problem. Click here to have it e-mailed to you.

Not Registered Yet?

Register now for FREE. Registration only takes a few minutes to complete. Register now »