The seal pup development project began in the summer 2010. The aim of the project is to try to understand and define 'well-being' in pups undergoing rehabilitation and the social and physical environments in which well-being may be maximised. The behaviour and body language of pups which we think indicates 'well-being' is already described in the section on pups' well-being under general care in rehab. However, these behavioural indices, and - conversely - behaviours and body language suggestive of stress or lack of well-being, may not be universally recognised.

The project began with a quantitative assessment of the behavioural development of pups of the harbour seal (Phoca vitulina). This was done by taking video of pups in the wild throughout the pupping season. Video clips were then analysed for the types of behaviour and the occurrence of different behaviours.

The results showed that pups almost always remained less than 1m away from their mothers, and were closest while mother and pup rested in the dry zone. Filial social interactions were most frequent in the water, least frequent in the dry zone and intermediate at the water’s edge; suckling occurred almost exclusively at the water’s edge. Our findings highlight the essential features of a harbour seal pup’s social and physical environment. We suggest how these features could be incorporated into the design and procedures of rehabilitation centres for ‘orphan’ pups. The paper was published as:

Wilson, S.C., and Jones, K.A., 2018. Behaviour of harbour seal (Phoca vitulina vitulina)
mother-pup pairs in Irish Sea intertidal habitats. Biology and Environment: Proceedings of the
Royal Irish Academy

This quantitative description of pup development may then be used as a baseline for comparison with similar quantitative descriptions of the development of pups in rehabilitation. A study comparing the behaviour of three pup pairs at TSR (Maxi&MIni, 2013, Ula&Earendil, 2014, and Coral&Pearl, 2016) with wild pups and their mothers has been carried out and a a paper with the results has been submitted for publication.

Mitigating the effects of maternal loss in harbour seal pups in captive care

Stranded newborn “orphan” harbour seal pups entering captive care are often maintained for some weeks in isolation, mainly as a precaution against the spread of infections. However, this practice raises concerns for the welfare and normal socialisation of pups, who normally spend their first post-natal weeks close to their mothers and other seals. Our study recorded and described the behaviour of six paired orphan pups in rehabilitation to about five weeks of age, provided with free access to water and haul-out areas. Behaviours compared quantitatively with the behaviours of wild pups with their mothers were: resting, body contact, nosing exchange, play, follow and suckling, and whether these behaviours occurred in the water, water’s edge or on the haul-out area. The pups entered the water every day, although more often from about 2.5 weeks of age. They displayed to each other the same behaviours that free-living pups display to their mothers, although they engaged in relatively more physical contact, body nosing, and aquatic play. Our study has shown that orphan pups maintained in pairs with free water access can act to some extent as mutual mother substitutes, thereby promoting species-typical primary socialisation and welfare during early rehab.

A further study of the changes in wild pups' behaviour with their mothers towards weaning and then the pups' behaviour with each other for the next 2-3 weeks, i.e. up to about 5-7 weeks of age). From about 2 weeks after birth, mothers sometimes left their pups at a particular rock, while they went fishing offshore, later returning to the same rock to collect them. While their mothers were away, and after they were fully weaned, pups rested together on this rock, interacted together in the nearby water and possibly started to fish together. 

Wilson, S.C. and Jones, K.A. 2020. Behaviour of harbour seal (Phoca vitulina vitulina) pups in Dundrum Bay, north-east Ireland, during transition from filial dependency to weaning. Proceedings of the Royal Irish Academy 120B(3), 187-202.

A 'Demand' feasibility study has also been carried out. For this, a pup is offered the opportunity to gain access to another pup, but must make a choice or overcome an obstacle in order to do so. In the case of 'orphan' pups, the obstacle would be appropriately small, such as a weighted door to push open or an object to be climbed over. A feasibility study was carried out at Mablethorpe Seal Sanctuary with pups Salt&Pepper in 2012 and TSR with pups Maxi&Mini" in 2013. A link to the report is attached below:

Does a harbour seal "orphan" in rehabilitation need a companion pup?


We have also been investigating biomarkers of 'stress' hormones from urine of pups kept in different conditions in different rehab centres. The aim of this was to gain insight into the physiological well-being of pups, and could be correlated with different conditions of care which offer different social and physical environments. The results from the urine samples indicated that pups with low body weight and low weight gain had relatively high levels of the glucocorticoid hormones prednisolone and prednisone. Concentrations of  cortisol and cortisone declined for pups with free water access (who also had other pups as companions), but did not decrease for pups with no access to water. The results of this study were published in 2023 as:

Wilson, S.C., Villanueva, S., Jones, K.A., Dmitrieva, L. and Smyth, W. 2023. Urinary glucocorticoids in harbour seal (Phoca vitulina) pups during rehabilitation.  Gen. Comp. Endocrinol. 335, 114227.