I admit: I’m no expert on seals. Like you, I know what they look like, I mean I’ve seen quite a few, mainly as a kid on my annual seaside holiday to North Norfolk. But I don’t really know much about them. Sound familiar? So, come with me on a journey as I delve deeper into their mysterious world.
Common or grey?
There’s just two resident seal species in the UK – the common (on the left here) and the grey (on the right). Confusingly, the common seal is actually less common than its bigger cousin the grey! Across the pond in America, common seals are actually known as harbour (ok, harbor) seals, and that’s a good name to describe its habits of living close in to land for most of the year.
Common seals are smaller with snub-noses, and there is very little difference between males and females, although males may be slightly larger. By contrast, the male grey seal is considerably larger than the female. Greys have a distinctive long snout – I’ve heard them described as having ‘Roman noses’. In fact, its scientific name (Halichoerus grypus) means ‘hook-nosed sea-pig’, a bit harsh perhaps, but it certainly does describe their appearance!
Coming ashore
Because seals are evolved from land carnivores and, unlike whales and dolphins haven’t evolved ways of giving birth at sea, they must return to land to give birth to their pups. Between September and November, grey seals haul out on rocky shores to have their fluffy, white-coated pups. They’ll then spend around three weeks ashore.
Common seals do it differently, coming ashore on sandy beaches and intertidal areas from May through to July. Their pups are more readily adapted to a marine life. They shed the white coat before birth and are born with well developed hind flippers, meaning that they have the ability to swim within just a few hours of birth. The mother and pup then spend most of their time together in the sea.
Diving
Here’s what I thought was the most interesting thing I discovered about seals.
Now, when you or I head under the water, we must take a deep breath – as do whales and dolphins. Seals however, do the opposite. They breathe out before diving, leaving very little air in their lungs. Whilst this seems counter-intuitive, it’s just one of many adaptations to a marine life.
Because there is very little oxygen in their blood, there’s no point in pumping it round their body. So, to overcome this a seal’s heart slows down, both in the number of beats and the strength of the beats. So when a seal is hunting underwater, it’s not breathing, and barely beating it’s heart! The oxygen is actually stored in it’s muscles, which are specially adapted. Upon returning to the surface, it must then inhale air quickly to recover. That’s amazing, isn’t it?
Sleepy seals
Seals can sleep in the sea, I found out. However, this can present a problem – they naturally sink! As I’m guessing that’s a bit of issue they normally haul out.
Can I see seals on RSPB reserves?
In short, yes! I’ve actually seen a common seal at our Ouse Washes reserve. Yes, that’s right, a reserve in land-locked Cambridgeshire! Admittedly, I uttered ‘what on earth is that?’ when I first saw its head poke out of the water. But, it turns out, common seals are not actually uncommon in fresh water rivers and have been known to travel several hundred miles upstream. Grey seals, on the other hand, are much less likely to enter rivers.
There’s a whole load more reserves where you’re much more likely to see seals though, let’s be honest, Cambridgeshire isn’t a seal hotspot!
Find out more...
Well, I’ve certainly learnt a lot about seals. Despite being mammals like us, they are brilliantly adapted and evolved for their mostly marine life.
Do you have any seal stories? Or have you ever seen one in a usual place? Let us know by commenting below.
Hi Snettisher
As Neil NI reported, seals do seem more easily spooked and flushed into the sea by kayaks. The collective memory is an interesting idea...not thought of that before. Our theories include the idea that if a seal catches a glimpse out of the corner of their eye of a kayaker, the outline low on the water might look like an orca....their only natural predator. Once they realise they were wrong, they are then usually pretty nosey about the kayakers. The secret is to always watch the seals reactions....if they are repeated looking at you, then you are already close enough. If the seals move towards the sea, then you are too close and need to back away quietly. if they enter the sea, ask yourself....would the seals have gone into the sea if you hadn't been there? If the answer is 'no probably not', then the seals have been disturbed. Of course the same applies to motorised boats. The secret is to travel parallel to the shore across the seals keeping a steady, consistent course with no change in engine sound.....predators slow to look at potential prey, so anything that takes an obvious interest in the seals could be a predator and will be treated with caution! Kayaks definitely cause more seal disturbance from our experience than any other form of sea going vessel. Obviously this is rarely deliberate, so no blame attached, but the more we spread the word about how to watch seals without disturbing them the better! Pembrokeshire has a good research record and papers about seal disturbance.
As for seals eating fish at the surface. This is a relatively rare sight....seals usually down their fish in one (their favourite food being sandeels)...unless it is too big of course! Conger Eels seem to fit that bill! Sounds like you had a great experience.