Adaptations To The Max — Wildlife At The Extremes of Altitude, Cold, Heat and Depth

from Wildlife Promise

Bar-headed geese migrate over Himalyas - Photo: Dan Rhoads, Migrations.

We have learned many things over the years about how animals adapt to their surroundings. These range from the long snout of an anteater, the double eyelid of a water dwelling alligator, to the recent discovery that the stripes on a zebra are visually confusing to flies and other biting insects and thereby protect them from a life of misery.

But some creatures have made more extreme adaptations than seem physically possible.  Here are a few examples.

The bar-headed goose migrates over the Himalayan mountain range – the world’s highest. To do this, they achieve heights higher than Mount Everest which is just shy of 30,000 feet. When these geese are flying nearly 6 miles up, they are in what mountain climbers calls the “dead zone” because the oxygen is impossibly thin and the temperatures are 40 degrees below zero. The good news is, however, that the geese can take advantage of the jet stream and a 100 mile per hour tail wind. A special mix of hemoglobin in their blood and an extraordinary tolerance for pain lets them complete the thousand mile trip in fine fashion.

Another high altitude adaptation is by sheer accident. Small spiders and aphids can get swept up from ground level in a windstorm and end up being carried four miles up where they can float, frozen solid, half way around the globe. A rainstorm or some other weather occurrence will eventually carry them back to earth where many will revive!

Some sizable animals are well adapted to the cold including whales, seals and penguins. But one surprising cold water dweller is the 12 foot long bluefin tuna. The bluefin spawns in the tropical waters of the Gulf of Mexico and the Mediterranean but its large size and calorie needs force it into colder waters where food fish are more abundant than in warmer regions. Their blood vessels are specially adapted to let them easily make this hot-to-cold transition.

There are amazing adaptations in desert environments too. The sand grouse of African deserts have an uncanny ability to find thousands of seeds in the sand, each day, that are blown in from distant places during storms. They also fly long distances from their nests to reach drinking water.  The males of the species have specially adapted breast feathers that soak up water at the watering spot so they can carry it miles back to the nest and offer a vital drink to their thirsty young hatchlings.

Big ears seem to make a difference in the desert too and it is not just for better hearing. Desert hedgehogs, foxes and rabbits have large ears that act as panels for the cooling of their blood and bodies. The American jackrabbit is a prime example. Its ear-to-body ratio is amazingly efficient at cooling these animals living in ground temperatures sometimes in excess of 130 degrees.

The dorcas gazelle wins the prize for desert adaptation. It does not drink water at all. It gets all of its moisture by ingesting desert plants and it does not urinate. Instead it discharges small dry uric acid “pellets.”

Many close-to-ground environments are dangerously hot. This can be a problem for birds called plovers that, worldwide, lay their eggs directly on sandy beaches and dune areas. The crab plovers of the Persian Gulf lay their eggs on sand that gets so hot it would literally cook them. But these birds have adapted to the hot surface and dig deep holes where the cooler sand at the bottom is better suited to egg hatching.

Flamingos are well adapted to both heat and the exploitation of quite toxic salt lake sites. They feed on specialized algae that grow in salt (soda) lakes and they nest by building small islands in the middle of waters so caustic that predators will not venture into them. They build these nesting mounds high enough that the wind will not blow toxic salt-laden mist onto the eggs.

Tubeworms - Photo: NSF

Another bird, Temmick’s courser of Africa has learned to take advantage of areas that have been burned over by wild fires. It feeds on the insects that have been baked in the fire and it lays ash-colored eggs that blend in with the burnt environment it prefers.Perhaps the champions of all adapted species live at the bottom of the ocean and congregate around thermal vents that emit water as hot as 600 degrees. The vents are a fairly recent discovery and have shifted some theories about the origins of life itself. These vents support a wide range of unique fish, crabs, shrimp, mussels and huge tube worms that live in water that is often near 150 degrees. What makes these adaptations scientifically amazing is that the vent-supported food chain is not based on sunlight, which is the universal source of life elsewhere in the world. Instead these creatures feed on bacteria that derive their energy from the sulfides the vents emit. They have adapted to an entirely unique food web and demonstrate how life manages to thrive in nearly any environment.

Learn more about how you can celebrate EXTRA-ordinary species during this year’s National Wildlife Week, March 19-25.