Adaptation is an evolutionary process resulting in changes or adjustments of a species, to better suit its environment. Species are constantly adapting to their environment, evolving features that allow them to have a better chance of survival in their habitat and often exploit new, sometimes challenging environments.
To better explain adaptation, we have chosen examples of species with features that allow them to live in arid habitats. In these extreme environments, species must battle against the heat during the day and the cold at night, whilst controlling their body temperature and preventing excessive water loss, as well as avoid predators and find food.
Ouch! It’s a bit hot underfoot
You might think that being big in a desert is a problem as larger bodies are better at holding heat, but this isn’t an issue for the ostrich, the largest of all birds. The ostrich uses its feathers to trap air, which creates a barrier between the outside heat and its body, cooling its body during the day and insulating it at night.
The lungs also have a well-developed air sac system that prevents over ventilation of the lungs and subsequent water loss, while the ostrich’s urine contains uric acid carried in a mucus-like substance that helps to minimise water loss.
Big ears are cooler than little ears
Another arid environment specialist, the kit fox also has curious adaptations to combat the blazing heat of the desert sun. As blood is pumped throughout the large and highly vascularized ears, the blood cools rapidly because it’s so close to the skin’s surface, regulating the fox’s body temperature.
The kit fox also has a highly developed digestive system designed for maximum water absorption. It rarely needs to drink because the stomach and intestines suck nearly all the fluid out of its prey.
Spiny on the outside, succulent on the inside
Though the kit fox and other animals have evolved water-saving strategies, plants are the true-masters of water-conserving adaptations.
Conifers, or ‘cone bearing’ trees, like the beautiful whitebark pine, typically have thin needles instead of leaves. The needle’s small surface area and waxy coating prevents water from being released by evaporation.
Cacti too have a thick waxy coating and shallow roots to help them save water. Found in extremely dry environments, where water is exceptionally scarce, they’ve also added a few extra adaptations for good measure: their prickly spines keep herbivores from feeding on them and depleting their resources.
Getting legless in the sun
A member of the aptly named sand-sliding skinks, the Mount Cooper striped lerista demonstrates extreme adaptation to arid environments, as it is specialised for ‘sliding’ through sand. Legs are unnecessary for this sort of locomotion and may even get in the way, so this skink has completely lost its forelimbs, while the hindlimbs are greatly reduced, with just one digit on each.
Give us your examples!
The examples we’ve described here are just a few of the hundreds of thousands of adaptations animal, plant, invertebrate, and fungi species have evolved throughout the course of time. Look through the ARKive collection and see if you can identify adaptations in our profiled species; we can assure you, big, small, hairy, scaly, or scary, every species has one!
Erin Matyus, Program Assistant, Wildscreen USA; Alex Royan, ARKive Species Text Author