Encountering Seals: Insights from Porth y Gwichiaid

At Porth y Gwichiaid, known as “winkle cove,” a dozen grey shapes bobbed in the green waters, captivating onlookers. Observers at Penrhyn Glas leaned closer, trying to discern whether they were witnessing seals or simply fishermen’s buoys. Despite varying levels of visual acuity among the group, one thing became clear: the silhouettes belonged to grey seals, a species that has adapted impressively to its marine environment.

As the group edged closer to the shore, the seals responded by lifting their heads higher out of the water, equally intrigued by the humans. Occasionally, one would slip beneath the surface, only to resurface at a distance, continuing their observation. This interaction prompted reflections on the evolutionary journey of these fascinating creatures.

The ancestors of modern seals, which are classified as mustelids alongside otters and weasels, made a significant transition from freshwater to saltwater habitats. According to Charles Darwin, this transformation involved crucial adaptations, particularly in their vision. While otters retain some color perception with two types of cone receptors, seals have evolved to lose one of these, resulting in a predominantly monochrome world. However, this adaptation has enhanced their ability to see in the low light of the ocean depths.

Seals are capable of diving to depths of up to 50 metres and can occasionally go much deeper. Despite their marine lifestyle, they return to shore to breed and spend the early weeks of their lives on land. To cope with the varying light conditions above and below water, seals possess a powerful iris that can constrict their pupils to a pinhole when exposed to bright sunlight.

Some paleoanthropologists suggest that humans may have also evolved along the sea’s edge, benefiting from its abundant food supply. The physiological parallels between humans and seals, particularly regarding adaptations to aquatic environments, offer intriguing insights into our evolutionary history.

As the seals and humans observed one another, a sense of wonder permeated the air. The encounter at Porth y Gwichiaid served not only as a moment of connection with nature but also as a reminder of the diverse evolutionary paths taken by different species.

For those interested in exploring more about the natural world, the book Under the Changing Skies: The Best of the Guardian’s Country Diary, 2018-2024, published by Guardian Faber, provides a collection of insightful reflections on nature and its myriad wonders.