Well it’s that time of year again – time to get Rocky out of his box – Rocky the remotely controlled vehicle – a modified 1/5 scale ‘Rock Crawler’ in fact. Why on earth would we want a remotely controlled vehicle on a seal colony you ask. Well, the main aim of our studies is to find out how individuals cope differently with ‘stress’ – our heart rate monitoring allows us to do this by looking at how individual heart rates change when mothers get involved in some ‘argy-bargy’ with their neighbours, or give over amorous males a bit of a good telling off!
That’s great – we can see how each of our individual study seals cope with the natural stresses that occur on a busy seal colony. However, one problem is that not all mothers will get into the same amount of aggro with their neighbours – some mums seem to prefer to pup in high density areas, close to pools of water, but at the cost of lots of hassle from other seals. Other mums seem to select rather quieter places, where there will be less aggro, but less access to pools of water (which the mums like to bathe in and drink from). So, that’s where Rocky comes in – by using Rocky we can present each female with the same mild stimulus, and see how they react, both behaviourally and in terms of heart rate.
Fortunately, a carefully and steadily driven Rocky causes little alarm amongst the seals. What we try to do is park Rocky a few meters away from a particular study seal, then once she has acclimatised to Rocky’s presence, we remotely trigger a sound stimulus (a ‘wolf call’ in fact). We can then see how each mum reacts to this standardised stimulus. The reactions are very mild, and involve the mums performing more ‘pup checks’ – where the mum looks towards her pup to check that it’s OK. What we find is that some mums do very few pup-checks in response to Rocky, whilst others increase their pup-checks compared to their normal rates of pup-checking. This gives us a good indication of a mother’s behavioural type. Using rocky enables us to perform this standardised test in the wild, without having to approach the seals ourselves, and so minimises disturbances to the seals.