Fish also shrink in winter

Wild salmon species tend to reduce body size so they can hide in shelter, to avoid a harsh winter.

The findings have been published by scientists from the Finnish Game Institute and the Fisheries Research Institute in Paltamo, Norway, after they found that immature salmon tended to reduce body length more 1cm and reduce body width by 10% in winter.

According to the explanation of the researchers, this activity can help them save energy during the winter days when food sources become scarce. This phenomenon has also previously been shown to exist in some small mammal species such as shrews and lizards, but has never been found in fish.

The case of animals with reduced body size in winter is most commonly known as sea iguanas - a popular reptile species in the Galapagos Islands. This species can reduce up to 20% of body length as a result of El Nino causing their food source to be scarce because it is too hot.

In salmon species, according to the scientists' description, the cause of this shrinkage is because they are " fed in the winter ". That is, their appetite has decreased significantly because they have eaten too much in the fall.

However, scientists still do not know exactly how body contraction works. But they surmised that perhaps this phenomenon in salmon is similar to that of shrews. It is caused by the mass decline of an adhesive that connects the spine and spine of the salmon.