Migrations

"Animal migration is a phenomenon far grander and more patterned than animal movement. It represents collective travel with long-deferred rewards. It suggests premeditation and epic willfulness, codified as inherited instinct." (David Quammen, 2010.NG)

These fascinating seasonal movements are carried by a handful of species that have developed this Darwinian way to perpetuate themselves through the generations. Oriented by temperature, light, currents, or even magnetic fields, these animals have proved to be an example of evolution and a great source of knowledge, especially in changing environments.

Migratory patterns usually involve special behaviours of preparation and arrival, and require great allocations of energy. From vertical migrations of copepods to the great migration of the monarch butterfly, or of the sperm whale, what drives these animals is truly a sense of larger purpose. It is stamped on their genetic code and they only know the way to go as they are moving.

Let's take the example of sea turtles;

The loggerhead turtle swims to specific beaches around the world to lay its eggs. After all eggs are safe in a sand hole, the mother leaves and will only come back to the same place a few years later. The younglings are born without any parental control and go to the water as soon as they come out of the egg. When they enter the water, there is an immediate trigger that tells them where to go and eventually, when they are fully grown, they come back to the same beach where there were born.

The same goes for the monarch butterflies, which take several generations to get to Canada where they produce a super generation of monarch butterfly that alone will return to the place it all started - Mexico.

It is essential that we understand the importance of these species and their migratory behaviours. This is not a topic of general culture and basic knowledge of our surroundings. It can contribute for a better management of our habitats. In a changing environment, their sensory cues may be masked and thus, their migrations delayed or advanced. Also, the seasonal presence of these animals will contribute for a greater diversity in the receiving environment, thus reducing inbreeding and loss of genetic variation. Changes in migratory patterns should be seen as a warning to humans that there is a great change in the environment that could also affect us.

Migrations are a fascinating topic and are a great source of knowledge that, if put in good use, can improve the state of our ecosystems.