When autumn comes we wrap ourselves in scarfs and overcoats and enjoy the changing seasons. Meanwhile animals start thinking about the issues of survival, because the beginning of the cold part of the year means that available resources will be scarce again.
But how do animals actually adapt to seasons? Scientists from the University of Edinburgh found a biological switch that helps animals make those important seasonal changes.
As nights become longer, nigh time hormones are released for longer, preparing the body for the colder part of the year. Image credit: Armineaghayan via Wikimedia (CC BY-SA 4.0)
Scientists studied sheep’s endocrine gland attached to the brain called the pituitary gland. They wanted to see how the activity of this gland changes in accordance to the length of the day. You probably know that humans as well as animals have energy daily energy rhythms and hormonal cycles that control our sleep and hunger.
However, nature provides us with different days and we have to adapt to the change as the months pass. Although scientists were studying sheep, they believe that the same principles apply to other mammals, birds and reptiles.
Researchers discovered that one of two possible biological mechanisms is activated within the pituitary gland depending on whether the day is long or short. During the periods of the year when nights are long, the brain produces hormones that prepare the body for the coming season. In other words, night-time hormones are released for longer. This affects many biological processes, such as reproduction and feeding.
Of course, when seasons are changing, the switch flips as nights get shorter – at that time biological processes linked to summer are triggered. This study showed that this hormone switch is controlled by a circadian gene known as BMAL2, found in many animals.
This biological switch affects most of body’s functions, such as fertility, fat retention, hunger, energy levels and so on. Because BMAL2 is found in many animals, scientists predict that this biological switch is active in many mammals, birds and even reptiles. Professor Simone Meddle, one of the authors of the study, said: “Fluctuations in hormones and behaviour are part of a delicate biological orchestra that is crucial to life. Many animals depend on seasonal changes in their biology to survive and our findings are a crucial part of the puzzle to understand the underlying processes”.
When you hear about animals preparing for winter, you think about their behaviour. Collecting resources, maybe preparing a place for hibernation, grouping up together. However, a big part of that preparation is biological. Our bodies have to prepare for the coming season and it is important to know how it happens. This knowledge could actually explain some seasonal health problems.
Source: University of Edinburgh