Welcome back to Weird Animal Questions, where you post or tweet your questions on anything animal and we answer a few every week.
Your questions were all about aquatic animals this time around, so let’s get right into the swim.
What’s the biggest known great white shark?—Kevin, California
Dana Ehret, curator of paleontology at the Alabama Museum of Natural History in Tuscaloosa, said via email that the biggest great white on record is a 19.6-foot-long (5.9-meter-long) female caught at Ledge Point, Australia, on March 22, 1984. (See great white shark pictures.)
Ehret said he thinks that there could be great whites as long as 21 feet (6.4 meters), and that tooth measurements suggest the legendary predators could have gotten as long as 27 feet (8.2 meters) in prehistoric times.
Kevin also wondered if there’s any chance the biggest shark ever, megalodon (Carcharocles megalodon), is still alive out there.
At 60 feet (18.2 meters) long and 77 tons, this beast ruled the ocean from about 17 to 2 million years ago. Could it be alive today? “No, no, no! Emphatically NO!” Ehret said. (Related: “The Real Megalodon: Prehistoric Shark Behind Doc Uproar.”)
What’s the biggest sturgeon found in the Great Lakes?—Dwayne LaGrou, Michigan
The Great Lakes’ biggest known sturgeon was caught in Lake Superior in 1922 and weighed 310 pounds (140 kilograms). The animal was estimated to be a hundred years old, according to the book Fishing the Great Lakes: An Environmental History, 1783-1933. Sturgeon can live up to 150 years.
According to the University of Michigan, sturgeon have been around for more than a hundred million years, though they’re fast-evolving fish, spanning 29 species. (Watch a video of a 1,360-pound [617-kilogram] sturgeon being hauled up in China.)
How do fishing spiders walk on water?—Ha Chu Ting, Malaysia
The combination of the fishing spider’s light weight (less than a gram); a waxy, water-repellent coating on their legs; and the surface tension of the water helps these water walkers stay afloat, according to a 2000 article in Natural History magazine.
Robert Suter, a biologist at Vassar College in Poughkeepsie, New York, found that fishing spiders (also called raft spiders) can “row” because their long legs create a dimple in the water’s surface. When they push, the dimple goes back with their legs, acting like an oar. They “gallop” by pushing down on their two front legs, breaking the water’s surface; the water pushes back, propelling the spider forward.
The arachnids can also sail by holding their two front legs up into the wind and letting the breeze push them along the surface. (Watch video: “Fishing Spider Eating Frog.”)
How many teeth do alligators have?—Ruth Wayne Garry
Our last question comes via Facebook from Garry, whose three-year-old granddaughter is all about alligators.
Alligators have between 74 and 80 teeth, according to the Smithsonian’s National Zoo, and the reptiles can regrow teeth whenever they need them.
In 2013 research, a team from the U.S., Taiwan, and China studied the alligator-tooth regeneration process and reported it could someday be artificially stimulated in human beings.