The scaly foot snail is not one you’d come across in your backyard garden. In fact, you wouldn’t find it in any garden at tall – it’s a marine mollusk, found only in the Indian Ocean. Not only that, they have been found only in four locations in that ocean, near hydrothermal vents over a mile below sea level. The conditions there are harsh, with crushing pressure and temperatures that reach 750° F. Not surprisingly, the scaly-foot snail is both unique and very rare.
This snail acquired its name because of the scales on its foot, that resemble a suit of armor. That is also how it got its nickname – the sea pangolin. It builds these scales, as well as the outer layer of its shell, to protect its soft squishy body by pulling iron sulfides from the water. Inside that soft squishy body is a large heart, relative to the snail’s body size. This helps the snail to survive in a habitat with little oxygen.
In addition to all of the above, researchers who have studied the snail do not think it actually eats. Instead it hosts bacteria provided by the vents in a large gland and lives off the energy produced by the microbes. Essentially the snail farms its own food in its gut, making the scaly-foot snail a chemoautotroph (new word!).
Yet again, another weather forecast looms on the horizon that promises nights well below 0° F. And again I find myself marveling at animals’ ability to survive such extremes, especially the birds who have not migrated to warmer climates. Many of them are so small! Yet nature has this all figured out and birds’ adaptations help the strongest of each species to survive. So how do they do it?
Photo Credit: USFWS / John Carr
Birds have a number of strategies. One of them is seek sheltered spaces. Birds will find hollows of trees, shrubs, or other crevices so they are protected from the worst of the weather. Many species also huddle together in these spaces! The group cuddle allows them to share body heat. While roosting and trying to stay warm, birds will puff up their feathers – on extremely cold days birds may look fat but they are just trying to keep warm! Fluffing feathers creates air space that heats up and traps warm air around their bodies, kind of like wearing your own down sleeping bag. Birds must keep their feathers clean by preening for maximum heat retention and insulation.
Another strategy to stay warm is to shiver! Just like people do, birds shiver to generate body heat. In addition, many birds go into a state of torpor at night. It’s like a controlled hibernation. Once they are all tucked in, birds will slow their metabolism which lowers their body temperature 10-20 degrees and conserves precious energy. In the morning, the birds warm themselves up and return to feeding to replenish their reserves.
But what about their poor feet? Nature’s got that figured out too. For starters, many birds’ feet are able to get very cold and stay functional, which keeps the birds from expending energy to keep their feet as warm as their bodies. Bird feet can stay near freezing because they are made up of mostly bone and tendon, with little nerve tissue or muscle that could sustain damage (like with humans). In addition, birds have a countercurrent heat exchange system in their feet. In this system, the arteries of warm blood headed to a bird’s feet run right next to the veins returning from the feet with cool blood. The warm blood heats the cool blood returning to the body, allowing the birds’ cores to stay warm without expending extra energy. Many birds will also tuck one leg up against their body or sit down in order to warm their feet. Some will even tuck their bills into their back feathers. Not only does this warm the bill, but it improves breathing efficiency because they are breathing in the warm air near their bodies, not the icy cold air around them.
And while nature does have all this figured out, if you are so inclined, put out extra bird seed on cold days so your feathered friends can replace the calories they lost trying to stay warm.
I discovered last week that manatees, elephants, and hyraxes are close relatives. Hyraxes? Hyraxes are small, furry animals that look like rodents. In fact they look a lot like guinea pigs or a rabbit with short ears.
Photo Credit – Dave Govoni
The rock hyrax is sometimes referred to as the little brother of the elephant. The hyrax and the elephant, as well as the manatee, are descendants of a hooved mammal, Tethytheria, that died out approximately 50 million years ago. And though at first glance there is a huge (pun intended) difference between these three relatives, their toes, skulls, and teeth have many similarities. On the hyrax, that includes incisors that are like tiny tusks. Elephants and hyraxes have flat, hoof-like nails (and even manatees have toenails on their flippers!) and specialized footpads. Finally, all three are highly intelligent animals and among the smartest on the planet.
These mysterious creatures live throughout Africa, as well as parts of the Middle East. Rock hyraxes live, as their name implies, in rocky areas in colonies of as many as 50-60 individuals. One of the most interesting things about hyraxes, to me anyway, is that they spend their first couple of hours every morning in a group cuddle basking in the sun! In fact, they dislike cool and rainy weather. If they poke their head out in the morning and don’t like what they see, they won’t even come out of their rock shelter. And while mostly diurnal, hyraxes will come out on a moonlit night (if the weather’s good!).
Their social structure reminds me of prairie dogs in that they live in large, social groups, create nurseries for the young, utilize lookouts that watch for danger while others eat, and have a variety of vocalizations to communicate. And yet, they are not closely related to prairie dogs at all. Evolution is a mysterious thing.
Manatees are gentle giants. By giant I mean the males can reach 3,500 pounds and up to 13 feet long (though the average adult is about 10 feet long and weighs around 1,000 lbs)! And yet they are gentle, lumbering creatures. Also known as sea cows, manatees are not predators, eating only plants. To feed such a body, manatees spend about 8 hours a day grazing and must consume 10-15% of their body weight every day. That’s like eating 3 bathtubs full of spinach.
Manatee swims near Crystal River National Wildlife Refuge. Photo credit Department of the Interior. U.S. Fish and Wildlife Service.
To do all of this grazing, manatees have a unique adaptation. They have prehensile lips, and the upper lip is split in two with each side moving independently. This allows the manatee to use their lips like fingers to gather vegetation and move it into their mouths! Inside their mouths they do have teeth (all molars), sometimes referred to as marching molars. When front teeth wear down they are replaced; new molars grow in the back and the entire set of teeth progresses forward over time. This process continues throughout the manatee’s lifetime.
These marine mammals live in both freshwater and saltwater, preferring calmer areas like canals, rivers, bays, and estuaries. In the winter, they migrate to warmer waters, often in canals near springs or near power plant water discharge locations. And while they are seen congregating in large groups during the winter, in warmer months manatees travel mostly alone. However, if they do run across another manatee, they will spend time socializing. In addition, calves will stay with their mother for up to two years.
Another fun manatee fact…their closest relatives are the elephant and the hyrax.