A sea that disappears twice a day
Between the Dutch mainland and the islands of Texel, Vlieland, Terschelling, Ameland and Schiermonnikoog lies the Wadden Sea. At low tide, large parts of the sea floor fall dry and turn into mudflats and sandbanks. This unique landscape is a UNESCO World Heritage Site, shared by the Netherlands, Germany and Denmark — and it is the perfect home for seals.
Seals hunt fish in the water, but they need dry sandbanks to rest, to give birth and to feed their young. When the tide goes out, you can often see dozens of seals lying on a sandbank, looking like big grey sausages in the sun.
Two different seals
- The harbour seal (Phoca vitulina) is the smaller and more common species. It has a round, dog-like head. Pups are born in June and July and can swim just a few hours after birth.
- The grey seal (Halichoerus grypus) is much bigger: males can weigh around 300 kg, which makes it the largest predator in the Netherlands. It has a long “Roman” nose. Grey seal pups are born in winter, around December and January.
From danger to recovery
In the 20th century, hunting and polluted water almost wiped out the seals of the Wadden Sea. Grey seals disappeared from the Dutch coast completely for centuries. Later, in 1988 and 2002, a virus killed thousands of harbour seals.
Then things changed. Hunting was banned, the water became cleaner, and some sandbanks became quiet zones where boats are not allowed. Today both species are doing much better, and grey seals have returned to breed in the Netherlands again.
If you find a seal pup alone on the beach, do not touch it. Its mother is probably hunting nearby. Keep at least 30 metres away and call a seal rescue centre.