Ask Your Weird Animal Questions: Spiders and Other Animals With Bite

We love getting questions with teeth, and this week’s Ask Your Weird Animal Questions tackles animals and their various bites. Keep your hands (and toes) away from these critters.
Why does the gavial have such a narrow snout? Do they have snout envy issues? —Tristan 

A gavial is seen at the Czech Republic’s Prague Zoo in 2008. Photograph by Yannick Tylle, Corbis

The gavial (Gavialis gangeticus), sometimes called a gharial, is a wicked-looking crocodile relative with quite the bite. The reptile sports an intimidating set of 106 to 110 teeth that are ”ideally suited for holding struggling prey such as slippery fish,” according to the National Zoo. (See National Geographic’s photos of crocodiles and alligators.)
That narrow snout has little resistance in water and is used to “whip its head sideways through the water to snatch prey,” according to ARKive.
The bulb on the end of the mature male’s snout is called a ghara—the word for “pot” in India—and may be used to make their calls resonate or to attract females.
Very interesting publication on arachnids. Are some fatal to humans? —Karina Feo, Uruguay
Our spider edition of Ask Your Weird Animal Questions prompted this question, and the good news is that death from spider bites—including black widows—are quite rare. (See video: “Black Widow: Most Venomous Spider in North America.”)
Even so, there are plenty of spiders that can do harm. For instance, brown recluse and sac spiders “produce necrotics, so that their venom causes the tissue around the bite to die.” Though the bite isn’t fatal, an infected wound could be, Jo-Anne Nina Sewlal, an arachnologist at the University of the West Indies, said by email.

A black widow with the telltale hourglass-shaped mark. Photograph by John Cancalosi, Alamy

Other spiders potentially fatal to humans are the Australian Sydney funnel-web spider and the similar-looking mouse spider. In South America, wandering spiders—including the Brazilian wandering spider, or banana spider, so named “because they are known to hitchhike across in shipments of bananas”—are also dangerous to humans, Sewlal said.
I’ve had a very hungry black widow as [a] pet and saw her pick up a dead fly from the bottom of her cage and hang it into her web. She proceeded to wrap it and suck it dry as she would have with live prey. Are black widows known to scavenge? —Renate, Santa Cruz, California
Will a black widow take a bite out of a dead insect? Actually, yes.
Maydianne Andrade, an evolutionary biologist at the University of Toronto Scarborough, said movement is what attracts these predators, which “find and detect prey using vibrations that are transmitted to them via their web.”
However, a research note published in the Journal of Arachnology in 1981 and sent to us by Catherine Scott, a student at Simon Fraser University in British Columbia, reported black widows wrapping and consuming dead insects in enclosures abandoned by other spiders.
“Most spiders also use chemical communication and their tactile sense to make sense of the world around them,” Andrade said.
“They may be able to detect potential food [dead prey] if they come into contact with it when exploring a new space or repairing their webs.”
Will iguanas bite your toes if they’re colorful?
Yes. I took author’s prerogative on a tidbit seen on the blog Virgin Islands Now, which says that peckish iguanas can mistake red toenail polish for flower petals—and that the reptiles might move in for a nibble. (Read about a pink iguana discovered in 2009.)
It’s more of a problem in areas where iguanas are used to people. In those areas, the blog suggests covering up red-painted toes to avoid unwanted attention.
Got a question about the weird and wild animal world? Tweet me or leave me a note on Facebook.

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