Animals have always fascinated me. The way the birds dance, the speed at which the falcons dive on their prey, the ferociousness of tigers while protecting their territory and everything else like this. Sometimes, it makes me curious, thinking about how did animals become what they are now? It appears that the answer to my question is evolution.

Evolution is a process in which organisms change their physical and behavioural characteristics in order to fit in the ecosystem they build, along with other organisms, that live in that specific environment. It is this process of evolution which has created the wide variety of organisms we see today. Darwin, the father of evolution, explained that animals evolve according to their selective habitat. He determined that the process is long involving several generations of a species until it finally evolves into a different species. He explained that each generation of offspring representing their parents’ characteristics developed the necessary adaptation, physically or behaviourally, for overcoming certain challenges they face in their habitat. An offspring who develops such instincts or physical characteristics, surpasses its siblings and cousins in the race of survival, passing its genes to the next generation. Generation wise such characteristics become more distinct, eventually creating a whole new species. This made me wonder if animals are even evolving in response to climate changes the world is experiencing right now.

Animals have been evolving since a long time in order to fit the challenges posed by climatic conditions. One such challenge a great shank of species face was climate change during ice age. Animals evolved into giants and developed insulative mechanisms for keeping themselves warm during the sheer cold in the ice age. However, with the rise of temperature, during the later period of the ice age, some animals failed to evolve in response to that transition of climate at the right time and so they became extinct. Others, that is, the present-day thriving creatures evolved the right way at the right time. That is how evolution works—the ones who change on time, survived and the ones who don’t, die. Animals are still undergoing the same phenomena of adapting according to climate change. Except for this time, they are evolving for the pyro age.

The term pyro age, which is used by scientists to describe this period of climate change caused by a rise in global temperature, has already become a serial killer. This rise in global temperature is initiated by the increasing insolation effect, which is a result of large emission of greenhouse gases due to anthropogenic activities. According to the Living Planet Report 2020, more than 4300 vertebral species faced a severe decline in their population (i.e., an average, of about 68 per cent). About one in every four species is facing extinction.

Apart from this, some species are behaving in an unnatural manner, leading to frequent conflicts between man and animal. In many cases, the conflicts don’t settle peacefully. Sometimes humans get injured and sometimes the animals. The rising human–elephant conflict cases in Assam, a north-eastern state in India, is one such example. Roads, railways and farms have been built in elephant corridors. Unable to figure out a safe route, the elephants, in many cases, get hit by trains and sometimes they end up destroying human property. Many elephants, especially the younger members of the herd, get stomped on when crowds of humans create chaos among the herd and sometimes when victims of their unintentional destruction retaliate. However, elephants have been observed changing their itinerant paths in order to prevent such conflicts.

But, how do animals feel the need for adaptation in the first place? Well, it appears that it is an instinct for them. Animals possess a genetic setting of changing either their behaviour, or their appearance whenever they feel it can be beneficial for their survival, and this occurs generation-wise. Similarly, several animals have adapted to catch up with the changing environment. For instance, the tawny owl (Strix aluco) found in Europe and Siberia, a species of medium-sized owl, changes colours according to season. To camouflage in winter, they change their feathers to pale grey and white and in summer they turn their feathers into irregular brown, creating a striped pattern. Now, as the climate is becoming warmer as well as snowfall is decreasing and summers are lengthening in their habitat, a population of owls in Finland have changed their routing and are now seen in brown for most of the year. Another example, the great tits (Parus major) have been observed to prepone their egg-laying time so as to match with the early spring. Because of the early arrival of spring, their caterpillars also start hatching before the natural due time. Such adaptation and changes in behaviour indicate the species’ intelligence. This too is linked to shorter winters and the lengthening of warm-weather seasons. Animals have been observed to evolve as a response to change in their natural environment.

But not all the species are quick to adapt, some don’t, and when they do, it’s too late. Speaking of adaption in response to change in the environment, a species of sea turtle (Eretmochelys imbricata) or hawksbill has failed to do that on time. As a result, the population of hawksbill turtle has fallen more than any other species in the previous decade. About 80 per cent of the hatchlings of hawksbills, which hatch on full moon nights, get disorientated by the lights coming from the towns corresponding to the beach. Hundreds of them get stuck in sewage drains, and thousands get crushed by cars. This species of turtle is among those who are unable to catch up with the manipulation of their environment by men. What could be more sensitive than a massacre of innocent baby turtles, that too on the first day of their life?

However, there also exists species which adapt, and there are species which change in order to thrive even when their environment is manipulated. Corals are adapting to resist bleaching in warmer waters, salmons are changing their migratory routine, squirrels are preponing their time of giving birth, snails are changing the regulation of temperature in their bodies and so much more. I used to think that only animals are smart enough to adapt in order to cope up in this pyro age. But it appears that I was completely incorrect. Following the paths of evolution, plants too, are adjusting their flowering and fruiting seasons and some have also been observed to manipulate certain processes like transpiration, growth and even photosynthesis so as to match the dynamics created by climate change.

Well, now my fascination towards evolution is rising like the global sea level. Speaking of changes in the marine ecosystem, Humboldt squids have been shrinking in size. From the bills of parrots to the wings of bats, they’ve increased in size. These are adaptations to encounter the rise in temperature, be it in the air or the water—from Anole lizards (Dactyloidae anolis) lengthening their toepads to resist blowing away by frequent hurricanes (which too is a consequence of climate change) to Arctic dovekies (Alle alle) changing their feeding habits. From Asian elephants (Elephas maximus) changing their migratory routes so as to prevent conflicts with men to deer adopting nocturnal behaviour. From house crows (Corvus splendens) increasing the usage of self-made tools to various species of bowerbirds (Ptilonorhychidae) using human trash as decorative items for their nests. Animals from all over the world are changing, either adapting to the change of climate or for living alongside the advancements made by human beings, without creating any conflict. 

Although climate change is creating an era of mass extinction, some astute animals have learned how to prevent its impacts. Animals are evolving. They were created by evolution and have been evolving ever since. And this is a good indication. Studying such cases also helps in conservation. When we know which species are leading the race for survival, we can work for the conservation of the ones who are at risk, and the fragile ecosystem they hold. Evolution is not an option, it is a must. Species evolve over time, in order to survive and eventually thrive in some of the most difficult environments created by climate change, which the earth is experiencing right now. Species change their behaviour and mutate their physical characteristics to keep up with the constant race
for survival, as they say “Survival of the Fittest”.#

Jnyanam Bordoloi, Std. IX, Faculty HS School, North Guwahati, Dist-Kamrup, Guwahati, Assam, India.