As October rolls around, along with it comes facing the reality that summer is long over and that we are now heading towards that time of year that can be safely assumed as wet, windy and pretty darn cold! However, given the opportunity to take part in this year’s grey seal pup monitoring, which I know all too well involves getting out and about in that extreme weather - having done it twice already, my desire for warmth, dry clothes and hot showers all but disappeared. Instead it was replaced with the exciting prospect of melting my sturdy biologists heart at the sight of big balls of white fluff growing and scrabbling around on our coastlines, trying to survive against all Manx weather odds! Moreover, the opportunity to observe some very interesting behaviour of the largest breeding Pinniped in the UK during one of the most fundamental stages in their life history left no question in my mind. Now where did I put my rucksack…
So off I ventured onto the Irish Sea. It was the first day of October and I, the first volunteer for the seal pup surveys, set off, laden with enough food to feed a small army and woolly jumpers bursting from the seams of my trusty rucksack, on board Scraayl a local purposefully built boat whose name translates to “shearwater” or probably “Manx shearwater” in this instance. Skippered by long running Calf trip operator Juan Clague, this boat has served the Calf of Man wardens with their weekly food deliveries for best part of 4 decades - or so I am told!
As I stepped onto dry(ish!) land my eyes casually gazed over South harbour, a site known to host seal pups in the past, but alas no white puffball to be seen just yet. So off I jumped into the trailer to be transported up to the farmhouse by the estate warden, Nick.
As fast as I could, my food was thrown in the fridge and I was out the door again, eager to explore the transformation of the Calf of Man from what is otherwise a seal sanctuary, into a hive of mating and pupping action!
Alas, it didn’t take long before I saw not only my first seal pup - Nelson (top), but several well-known faces to the grey seal catalogue, notably #16 - Lambchop (middle) and number #17 - Eva (bottom)!
So here comes the science! The grey seal surveys are composed of three elements, firstly a seal pup census - noting how many pups are born and where, and, additionally observing their transition from stage 1 pups – poorly coordinated, thin pups with lanugo (white coat which insulates them until they develop a thick blubber layer) up to a stage 5, a fully moulted, weaned and mobile pup.
Secondly is behavioural observation, looking into how a grey seal budgets its time and additionally the variance in the observable behaviour between mother and pup.
Lastly, and this is where Lambchop and Eva come in, is photo identification of seals. This involves photographing where possible both the left and right hand side of the seals head to reveal a picture showing their unique pelage pattern. As the spot patternation seen on a seal is essentially like that of our fingerprint - never changing, by gathering photos over time and using recognisable marks to trace individuals we can explore the idea of site fidelity to the Calf. Moreover, it can also provide us with finite details such as whether the same mothers return to precise pupping sites or not? For example, both Lambchop and Eva have been seen every year consistently since 2010 making this their 5th year running. Furthermore, Eva has pupped every year at Cow harbour, a popular gently sloped shingle beach, whilst Lambchop has in the last two years moved from Cow harbour to Grants harbour which is right next door!
Don’t forget to check back for the next installment tomorrow! Trust me it’s worth it, it’s where all the cutesy seal pup bits come in!
Now where were we…? Oh yes…
During my time, I was happily exposed to the intricately timed and cleverly strategized process of reproductive behaviour in grey seals. Talk about killing two birds with one stone! Not only do both males and females fast during the whole mating season (females ~20 days, males ~50), but once the mothers have weaned their pups they waste no time finding a suitor to sire the next years pup! They are quite the example of parental investment, dedicating most of the year to reproductive efforts that include an 8 month gestation period, weaning their pup (~18-20 days), and then immediately mating which is followed by 3.5 month delayed implantation before the process starts all over again!
Image: Nelson, Eva and male in background.
Now unfortunately although seal pup monitoring can sound reminiscent of the feeling you get from a fuzzy warm Disney film on a rainy Sunday afternoon, it’s not always happiness and light, instead with it comes the stark reminder of the reality of rearing a young pup in an almost altricial state (highly dependent on the mother at birth) on often very exposed coastlines. Although grey seal pups soon enter a more precocial state whereby they become more coordinated and independent, those initial days often determine whether or not a pup with make it.
Interestingly, yet saddening as it was, I was witness to several pups battling for their lives on a particularly stormy day whilst on the Calf. During my stay the weather threw me into Autumn with no hesitation and as I sat overlooking one well known pupping site - Ghaw Lang, noting how ferociously the waves were crashing in, I could only hope that any one of the four pups that had been born there would make it. The tension and invariably the excitement tinged with sadness evoked by the harsh image of a lioness stalking her vulnerable prey on a David Attenborough esq programme on the telly, cannot rival the sad scenes that were before my eyes that day! My entire hardened scientific demeanour I have spent the last few years cultivating, soon departed to be replaced with an (almost) blubbering mess at the sight of the young offspring of an animal that has dedicated so much of their life to, being literally cascaded into the gaping jaws of the next oncoming wave. To put it in short, it was a sad but a harsh reality that cannot be ignored. There was no mistaking Darwin's most famous theory of evolution by natural selection in this scenario. Put quite simply, the mothers that chose the sites offering the greatest protection for their pups, were more likely to have offspring that went on to survive, continuing their genetic success and increasing their overall fitness.
Unfortunately, this year’s weather has not been kind and by the end of my time I estimated around 8-9 pups had lost their fight for survival. That totals more than any number of mortality seen during a pupping season there, let alone during only one week of it.
Blimey! I think I need to redeem myself with some happy nice memories now!
Pups, pups pups...
So in the time I was on the Calf of man, there were 24 pups born at 10 different sites, each recorded and recognised with a name beginning with the letter N to help keep track of who is who – believe me it’s harder than you think! I found myself trawling my mind for names and even went to the extremes of naming one ‘Nathaniel’ as it was all I could come up with at the time! My favourite though has to be ‘Nostradamus’, I think that pup is going to go far!
What is apparent when observing the grey seals is that there are such obvious differences in the way the pups are tended to by their mothers. Some are almost constantly attached to one another whilst other pups are left for hours without a peep from their mothers whatsoever. This is also often reflected in the behaviour of the pups themselves, some being all too eager to be taught how to swim by their mothers whilst others, often those alone on the shore for long periods, flee to higher ground at the mere splash of water! It makes you wonder how those individuals take to their first transition from land to sea. I expect if your stomach is rumbling enough, you soon get over your fears!
Talking of rumbling bellies… I am off for my tea. See you tomorrow for the last installment in our seal saga!
I was lucky enough to observe several behavioural aspects of grey seal life, the first being the suckling process between mother and pup.
Often the process is initiated with a vocalisation from the pup (strangely, it sounds like they are shouting mum….Honestly it does!), followed by the mother moving towards the pup whereby a brief touch of noses communicates they are the belonging pair.
When the pups are very young, they are very poorly coordinated and typically whichever way they need to move, they always seem to go the opposite! The mothers however, are very good at helping to goad them in the right direction. Often they will use their fore flippers to scratch and coax them to the teat, or, nuzzle and mouth at them until they get it right. Alternatively, the mothers will arch their hind flippers and pivot round towards the pup, to allow better access.
A suckling bout itself is often very short-lived, lasting anywhere between 5-15 minutes on average, but then again with a milk fat content of ~ 60% they probably don’t need much at a time! Gold top has nothing on seal milk!
You can't help but feel sorry for those mothers that end up adopting the most awkward of positions to sate their offspring!
***Note: You may want to avert your kid’s eyes for this section!***
As mentioned earlier, during the pupping season the male (bull) and female (cows) will mate once a female has weaned her young, or for those without young, any time during the mating period. I was lucky enough to observe this courtship behaviour, which for three individuals culminated in quite a funny story.
During the pupping season, males will aggregate around rookeries (pupping sites) and linger until they are offered the opportunity for a mating, and although bull seals are polygynous (meaning they will mate with several females during a season), they will still invest quite a lot of time in trying to secure a mating opportunity with an individual female. So there they were, a male and female on the shore for several hours, the male desperately trying his hardest to win the affections of the female until she upped and left, got into the water and immediately began mating with another male that had also been hanging around. Although the females are also polygynous and will generally mate with more than one male, you couldn’t help but feel a little sorry for the bull who had invested so much time pursuing her, only to be harshly rejected at the last minute!
Hopeful male sidles up to female...
Rejected for another!
Although these two bulls never came to blows whilst I was observing, I have in the past been witness to territory-related fighting behaviour between bull seals, whereby each will compete in order to try maintain sole access to females within a loose territory. Put it this way, I wouldn't want to be the one trying to break up the fight!
I have been asked many times about the mating of grey seals so I thought I would give in and write, somewhat uncomfortably about it here! I have to say that for a large mammal, the act is surprisingly gentle and long lasting. Mating can occur both on land, and in the water, and tends to follow the same pattern, whereby the female will present herself to the mate by vocalising and holding one fore flipper up to the air whilst simultaneously making a scratching movement, then if met with no resistance, the male will gently grasp the female behind the neck and both will spiral around one another.
Notably in my experience, there is very little vocalisation between the two parties during copulation, something many people find unusual, however there are lots of alternative communication displays that involve mouthing, nuzzling and teeth displays.
The duration of mating will vary but this particular time lasted the best part of an hour!
No wonder they look so pleased with themselves!!!
I could spend forever writing about my time on the Calf of man and the fascinating insight into Grey seal behaviour but it must come to an end at some point. So I will leave you with one of my favourite memories of my time there. An extraordinary sight, something that I personally haven’t witnessed before, there I was, sat conducting some behavioural surveys in the pouring rain, wind howling at my feet when out of nowhere an adult grey seal fully breached! With spectacular gusto, this rather large animal erupted from the water right before my eyes in an amazing fashion! It was truly incredible, and, low and behold was later followed by the sight of a full rainbow lighting up the sodden hilly landscape. A definite reward for persevering in the Autumnal weather!
Here are just a few of my favourite pictures of my time on the Calf of Man. Thank you to the Manx Wildlife Trust for having me and to you guys for reading!
Goodbye for now!
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