Sand flying, the males grappled. Tearing chunks out of each other’s necks; the fur was matted with blood. In the background, another pair had kicked off—approaching each other with open mouthed threats, bodies slapping the ground in percussive rhythm. Further out still a small male was sprinting (if you consider the quick shuffle-hop movements seals make ’sprinting’) away from his pursuer, hind flippers whipped forward with each hop to keep them out of range of the teeth behind.
Last year that was a typical Tuesday morning.
Three weeks ago, when I stepped off the boat on the Isle of May, I was immediately struck by the general lack, or seeming lack, of male grey seals about. If I scanned the rocks carefully I could spot one languidly sleeping. Then, perhaps 200m away and across a gulley, another sat in a pool of water, just his nostrils poking above the surface like a hippopotamus. It has now been three weeks, and I have seen ONE proper fight between a pair of males, and the number of threat displays could easily be counted on two hands.
One reason for coming out to the May this season, other than to help with the heart-rate behavioural study, was to take a step back and gain some perspective on my own work with male behaviours; of which I have spent the last three years neck deep in (and have spent the last two years telling you about on this blog!).
The site where I did all my work was a fascinating system: tidally influenced, open access, exposed to potential anthropogenic disturbances and expanding in size. It was an ideal place to think about some of my questions of male aggression, signaling and evolution of behaviours. From reading papers and talking to Sean, who did most of his previous work on the island of North Rona, I knew my site was atypical in many ways….but it is different to read about something and to see those differences in person.
The most obvious difference is the topography. Whereas Lincolnshire coasts are flat as a Sunday pancake, Scotland is rugged. Rocks strewn about as if a giant was playing Bowls. Gulleys so steep and narrow that a group of 300 Spartans could use them to block an invading army. Rabbit holes everywhere (of which my ankle seems quite good at locating…).
And as far as a casual observation goes, it seems that the male seals could be taking advantage of the landscape, or at the very least, the landscape could be shaping their behaviours. For example, I have seen some males sitting atop rocky outcroppings. Perhaps to gain a vantage point which will allow for monitoring the encroachment of challenger males? Other males position themselves at the mouth of a gulley; monopolizing access to the females beyond?
Most interesting is the sheer lack of males relative to females. At my study site, the ratio was approximately 2 females per male. So in a study area with 60 females I had 30 nutter-butter boys running around at any given time. Here, in a location called “Cross Park”, old dry stone walls block off the access on three sides of a grassy field. Inside the walls, approximately 11 females are raising their pups, with only one male within Cross Park, and another male on the slope beyond.
So, if the local topography is aiding males maintain access to females, are there certain areas, like Cross Park, that are more desirable? For how many breeding seasons can males maintain a position like the one at Cross Park? What are the costs associated with getting to such locations from the sea (Cross Park is quite far inland—suggesting a male might have had to get through other males to get there in the first place!) and do some males adopt less costly or less risky strategies?
Another great aspect of coming out to the Isle of May is the collaboration and opportunity to throw around ideas with other researchers whom are investigating other aspects of grey seal biology/ecology. So many of our coffee talks, dinner arguments and hypotheses thrown out over a pint of beer have given new light to how I see the results of my thesis. There is such a thing as ‘not seeing the forest for the trees’ and after three years embedded in a very niche topic, such opportunities to openly discuss science are vital to current and future research. Science is itself, a process of evolution.
For as the great David Attenborough said:
“The most extraordinary thing about trying to piece together the missing links … is that when you do find a missing link and put it in the story, you suddenly need all these other missing links to connect to the new discovery. The gaps and questions actually increase.”