Mediterranean Monk Seal ( Monachus monachus )

/ / Marine Mammals


Medium sized phocid that can reach up to 2.8 m in length.  They often weigh between 300-330kg, with the females being slightly smaller than the males.  The adult male’s fur is black or brown, while the adult female is light brown or grey.  Monk seals are easily identified due to the white patch of fur on their underside. On a male, the while patch only occurs on the stomach, whereas on a female, the patch starts under the neck and runs the full length of the body.  This means that the animal can be sexed non-invasively (1).


Monk seals very rarely haul out on open beaches and prefer to use caves with sea entrances.  In ancient times, the Mediterranean monk seal was known to inhabit open sandy beaches and shoreline rocks (4).  It is thought that the occupation of sea caves is a recent adaption as a response to the increase in human pressure.

Life Cycle

Monk seals become sexually mature between four and six years old and the females are able to give birth to one pup every two years.  Reproductive method is unknown but it is thought they establish breeding grounds. One theory suggests that males and females inhabit different areas and the females go to find the males, while another they suggests that a single male possess a territory with numerous females and breeds with those females only.  Pregnancy lasts up to 11 months and there is no set breeding season.  Pups are born in caves that have underwater entrances and during the first week after the pup is born, the mother remains in the cave at all times.  Aguilar et al (2007) noted that all pups suckled for at least 98 days, with the average being 119 days.  This is much longer that the lactation lengths observed in other phocids (3).


Having previously occupied a large geographical range throughout the Mediterranean and extending as far as the Azores, the monk seals distribution has been reduced to two main populations, one in the northeaster Mediterranean and the other in the northeast Atlantic, off the coast of northwest Africa.


As monk seals are very sensitive to disturbance, pregnant females will often abort if they feel threatened (2).  They are often also shy and reclusive


Monk seals are carnivorous and catch their food by diving, mostly during the day. Salman et al (2001) examined the stomach contents of two seals from the Aegean Sea and found by weight, 94% of the contents were cephalopods.  A small amount of Sarcotragus sp. and Posidonia oceanica was also found in the stomach contents of one of the seals, but this was assumed to be due to hunger and is not a regular choice (5).

Conservation status

Critically endangered under the IUCN Redlist (6).

Appendix 1 and 2 of the Bonn Convention

Appendix 2 of the Bern Convention

Appendix 1 of CITES

Annex 2 and 4 of the European Community’s Habitat Directive.


Description written by Kathryn Woodward (2009)

(1) Gilmartin, W.G. & Forcada, J. (2002) Monk seal – Monachus monachus, M. tropicalis and M. schauinslandi. In: Perrin W.F., Würsig, B. & Thewissen, H.G.M. (eds) Encyclopaedia of marine mammals. Academic Press, San Diego, USA. 756-759

(2) Johnson, W.M. & Lavigne, D.M. (1998) The Mediterranean Monk Seal: Conservation Guidelines. 2nd ed. Ontario: International Marine Mammal Association Inc.

(3) Aguilar, A., Cappozzo, L.H., Gazo, M., Pastor, T., Forcada, J. & Grau, E. (2007) Lactation and mother–pup behaviour in the Mediterranean monk seal Monachus monachus: an unusual pattern for a phocid. J. Mar. Biol. Ass. U.K., 87, 93-99.

(4) Monachus Guardian (2009) Mediterranean monk seal (Online) Available: Dates accessed: 23.03.2009

(5) Salman, A., Bilecenoglu, M. & Güçlüsoy, H. (2001) Stomach contents of two Mediterranean monk seals (Monachus monachus) from the Aegean Sea, Turkey. J. Mar. Biol. Ass. U.K., 81, 719-720.

(6)  Aguilar, A. & Lowry, L. 2008. Monachus monachus. In: IUCN 2009. IUCN Red List of Threatened Species. Version 2009.1. <>. Downloaded on 10 June 2009.