Environmental conditions in animal habitats often vary frequently. In some cases, these changes can be extreme, causing temperatures to eventually reach drastic values for the species. In these situations, factors such as the availability of water and food also have important fluctuations, so that the animals are exposed in a compromising way. In this sense, various individuals have developed certain strategies to cope with these events because, otherwise, they could die.
In this article on our site we will talk about one of those processes, which is known as aestivation. Read on and find out its meaning and examples of animals that estivate.
What is aestivation?
Aestivation is a dormancy process into which certain animals that live in areas where there are enter seasons with increased temperatures, which also affect the development of prolonged droughts. In this sense, animals that aestivate minimize their metabolism, reduce breathing, heart rate and, in general, their entire system enters a state of lower functioning, so that their temperature also drops, they retain moisture more efficiently and even the metabolic pathways at the cellular level of the individual are reorganized to guarantee survival.
Thus, aestivation is a state of dormancy in which various animals, both invertebrates and vertebrates, enter moments of drought. In certain cases, it is estimated that it is more the availability of water than the increase in temperatures that triggers aestivation. On the other hand, this strategic mechanism has been present in animal biodiversity for thousands of years, and although it is not used by all animals, a curious feature is that it does occur in very different taxonomic groups.
Animals that estivate
Now that we know the definition of aestivation, why it occurs and when, you are probably wondering which animals carry out this process. There are several species capable of developing this process considered as an evolutionary adaptation. In this sense, let us know certain examples of animals that estivate:
- Milk snail (Otala lactea): corresponds to a mollusk of the gastropoda class, being a terrestrial snail that lives in the Iberian Peninsula, Morocco and M alta, among other countries, has also been introduced in America. This animal performs aestivation in times of drought or food shortage, slowing down its metabolism, especially certain cellular processes.
- African Clawed Frog (Xenopus laevis): Native to southern Africa, this amphibian has also been introduced to Europe, North and South of America. This animal is mainly aquatic, but in times of extreme drought, when the bodies of water dry up, it is able to bury itself in the muddy bottoms that remain and remain motionless for up to a year, waiting for the water in the habitat to be renewed.
- Alfalfa weevil (Hypera postica): among the various insects that aestivate we can mention this beetle, which has a wide distribution in Europe. In the summer time, when it is in the adult phase, it enters this type of lethargy in which its respiratory and nervous functions mainly decrease.
- Freshwater Crocodile (Crocodylus johnstoni): This Australian endemic species inhabits various types of freshwater bodies, which They can decrease significantly during the dry season, so it uses the aestivation strategy to survive in the aforementioned season.
- Desert Tortoise (Gopherus agassizii): This tortoise, native to the United States and Mexico, varies its activity depending on the area where it lives, so that in those ecosystems where the summers are dry and with high temperatures, it enters a state of aestivation. In fact, the aestivation of turtles is one of the best known, since these animals, contrary to what is believed, do not hibernate, but enter the state of lethargy mentioned here or make use of brumation.
- Freshwater crab (Austrothelphusa transversa): in this case we have a crustacean native to Australia, which in the breeding season also summer drought. It inhabits seasonal rivers and builds an underground burrow, which it seals to maintain some moisture, and there it remains in a lethargic state until the rains return and the body recovers water.
- Thick-tailed Dwarf Lemur (Cheirogaleus medius): Although it is less common to find estivating mammals, this species of lemur native to Madagascar it enters this state during the dry season in its habitat, which can last around 6 months. During this time, the animal inactivates inside a hole in a tree, where it remains fully coiled, using the reserves it stores in its tail to survive during torpor. Additionally, the animal varies its body temperature according to the environment.
As you can see, the examples of animals that aestivate are very varied and do not belong to a single taxonomic group, something really curious, don't you think? If you want to know more Curious facts about animals, do not miss this other article.
Difference between aestivation and hibernation
The main difference between estivation and hibernation is that estivation occurs in habitats where water is scarce and temperatures rise, while Hibernation occurs in environments where temperatures drop very considerably, below 0 ºC.
On the other hand, aestivation can occur in vertebrate and invertebrate animals, while hibernation, although it is used as a very In general, it is actually traversed by certain mammals such as ground squirrels, jumping mice or marmots, among other related species.
Another difference between aestivation and hibernation is that animals that aestivate can come out of this lethargy much faster than animals that hibernate, which usually require more time to recover and resume the normal rhythm of their metabolism and body functions in general.
