10 May 2015

Mother knows best! Don't we all agree?



Harp seals (Pagophilus groenlandicus) are famous for being white and fluffy, which makes them adorable; but did you know that the white harp seals we see are pups? Adults on the other hand are black-faced with silver-gray body [1].
 
(Young harp seal suckling, photo by M. Watson posted www.arkive.org)

Like any other mammal, there is a special bond formed between the mother and her young. In the case of harp seals, the mother “noses” its offspring immediately after its birth not only to recognize its scent but also for her to be able to find her pup after foraging [2, 5]. Foraging takes a few hours a day and the mothers need to eat more during the nursing phase (which lasts about 12 days) to provide milk to their pups [3, 4, 5]. They also use their sense of smell to protect their young by detecting predators on ice [1], and to get back to their pups in case there is a need to relocate them due to the unstable ice floe where they gave birth on. [6]

Newborns are sedentary and weigh around 20 lbs which is almost nothing compared to a well fed adult at around 300 lbs. [2, 6] The pups can gain an average of 5.5 lbs per day, because their mother’s milk contains 25 to 40% fat in comparison to a cow’s milk that only contains 5% fat [2]. As soon as the pup fattens up and the nursing period ends, they are then ready to live on their own. The mothers swim off leaving them on the ice in search of a new mate.

Quite a short time to start becoming independent, huh?

To know more about harp seals, visit SeaLifeBase.
__________________________ 

[1] Lavigne, D.M. (2009) Harp seal Phoca groenlandica. In pp. 542-546, Perrin, W.F., Wursig, B., Thewissen, J.G.M. (2009) Encyclopedia of Marine Mammals, Second Edition. Academic Press: London. 1316pp.
[2]  Dougan, J.L., & Roland, K. (1982). The Ice Lover: Biology of the Harp Seal (Phoca groenlandica). Science, New Series 215(4535):928-933.
[3] Ellis, R. (2003). The Empty Ocean. Island Press, 367p.
[4] Innes, S., Lightfoot, N., & Stewart, R. E. A. (1981). Parturition in Harp Seals. Journal of Mammology 62(4):845-850.
[5] Lydersen, C. & Kovacs, K. M. (1999). Behaviour and energetics of icebreeding,
North Atlantic phocid seals during the lactation period. Marine Ecology Progress Series 187:265–281.
[6] Van Opzeeland, & I.C., Van Parijs, S.M. (2004) Individuality in harp seal, Phoca groenlandica, pup vocalizations. Animal Behaviour 68:1115-1123.

Written by:





No comments:

Post a Comment

What do you think? Share your thoughts with us.