This week on Ask Your Weird Animal Questions, we’ve assembled some parts questions for a column on animal anatomy.
Would love to know if [narwhals] use [their] tusk in some type of defense.—Jancito Reynaga
This question arose from the story “Narwhal’s Trademark Tusk Acts Like a Sensor, Scientist Says,” which said that the narwhal‘s tusk—actually a tooth and found mostly on males—acts like a sensory organ, detecting information such as food sources or ocean salinity.
The spiraled tusk, which protrudes through the whale’s lip, has inspired comparisons to the horn of the fabled unicorn.
According to the University of Washington’s Kristin L. Laidre (who, as the story notes, opposes the sensory organ theory), the tusk likely isn’t used as defense.
That’s because generally tuskless females “still manage to live longer than males, and occur in the same areas while additionally being responsible for reproduction and calf rearing,” according to her website.
We’re all aware that a dog’s nose is meant to be cool to the touch … but why is that?—Charles Martin via email
It’s commonly thought that a dog’s nose should be cold and wet, but “the reality is, veterinarians don’t think much about a dry or wet nose, except in cattle—a sick cow stops cleaning her nose with her tongue!” Julie Meadows, of the School of Veterinary Medicine at the University of California, Davis, said via email.Patches, a rescued dog, sniffs its owner. Photograph by Lynda Folwick, National Geographic Your Shot
More important things to monitor around a dog’s nose are crusting or scabbing at the top of the nose (where the nose meets the hair of the muzzle) or discharge. Watery or slight white discharge isn’t a concern, “but yellow, green, or blood would be worrisome,” Meadows said.
I want to know the parts of a tapeworm.—Jason Peace Deus, Shinyanga, Tanzania
According to the book Infectious Diseases, there are about 5,000 species of tapeworms, or parasitic flatworms, that can infect all types of animals, including people.
Kennesaw State College of Science and Mathematics in Georgia offers this diagram of basic tapeworm anatomy, including proglottids—segments containing both male and female reproductive organs—and the scolex, which contains suckers and hooks used to attach to the host.
Tapeworms don’t have a mouth, digestive tract, or circulatory system; they absorb food through a tough body covering. The Uniformed Services University of the Health Sciences in Bethesda, Maryland, offers detailed images of the reproductive system, and Patient.co.uk gives comparative lists of anatomical differences between species.
My dog was full grown when I found her and the vets said she’d probably been feral her whole life. All of my other dogs have/had rounded nails. Her always comes in curved and super thin and sharp at the end like a cat. Is this normal for dogs at all? Do feral dogs grow their nails sharper?—Victoria Lawrence via Facebook
No. Being feral is a psychological not physiological state, so a feral dog wouldn’t have different physical traits from a domestic dog, no matter the breed, said UC Davis’s Meadows.
“Dogs that are labeled ‘feral’ often have behavioral concerns because they missed out on the golden opportunity for socialization to people and other animals when they were puppies—that door closes at about four months of age,” Meadows wrote. (See “Stray Dogs in Sochi: What Happens to the World’s Free-Roaming Canines?“)
“Because of that, they are often anxious or even fearful. That might lead to fewer outings from the house and less activity on harder surfaces, which would result in less wear on the nails and the need for more frequent trimming.”
Those harder surfaces—asphalt, cement driveways, or sidewalks—cause normal claw wear and tear. Dogs who don’t get much friction on their nails, like lap dogs or older dogs, might have sharper nails, she said.