As of 2015[update], it is estimated that fewer than 700 individuals survive in three or four isolated subpopulations in the Mediterranean, (especially) in the Aegean Sea, the archipelago of Madeira and the Cabo Blanco area in the northeastern Atlantic Ocean.

The monk seals' pups are about 1 metre (3.3 ft) long and weigh around 15–18 kilograms (33–40 lb), their skin being covered by 1–1.5 centimeter-long, dark brown to black hair.

[9] Pregnant Mediterranean monk seals typically use inaccessible undersea caves while giving birth, though historical descriptions show they used open beaches until the 18th century.

One cause of this low survival rate is the timing of high surf around the areas of breeding, creating a threat to young pups.

However, it is believed to be common among monk seals of the Cabo Blanco colony to have a gestation period lasting slightly longer than a year.

[12] Mediterranean monk seals are diurnal and feed on a variety of fish and mollusks, primarily octopus, squid, and eels, up to 3 kg per day.

In ancient times, and up until the 20th century, Mediterranean monk seals had been known to congregate, give birth, and seek refuge on open beaches.

[1] It may be locally-extinct (extirpated) in and around Albania, Corsica, Egypt, France, Italy, Libya, Malta, Monaco, Montenegro, southern Spain (and the Balearic Islands), and Tunisia.

[1] Several causes provoked a dramatic population decrease over time: on one hand, commercial hunting (especially during the Roman Empire and Middle Ages) and, during the 20th century, eradication by fishermen, who used to consider it a pest due to the damage the seal causes to fishing nets when it preys on fish caught in them; and, on the other hand, coastal urbanization and pollution.

[1] Monk seals were present at Snake Island until the 1950s, and several locations such as the Danube Plavni Nature Reserve [ru] and Doğankent were the last known hauling-out sites post-1990.

[23] These two key sites are virtually in the extreme opposites of the species' distribution range, which makes natural population interchange between them impossible.

The increase of sightings in Sardinia suggests that the seal occasionally inhabits the Central Eastern Sardinian coasts, preserved since 1998 by the National Park of Golfo of Orosei.

[28] Cabo Blanco, in the Atlantic Ocean, is the largest surviving single population of the species, and the only remaining site that still seems to preserve a colony structure.

While opinions on the precise causes of this epidemic remain divided between a morbillivirus or, more likely, a toxic algae bloom,[1] the mass die-off emphasized the precarious status of a species already regarded as critically endangered throughout its range.

[35] On 31 December 2010, the BBC Earth news[36] reported that the MOM Hellenic Society[37] had located a new colony of seals on a remote beach in the Aegean Sea.

[42] On 9 September 2013, in Pula a male specimen swam to a busy beach and entertained numerous tourists for five minutes before swimming back to the open sea.

[43] In summer 2014 sightings in Pula have occurred almost daily and monk seal stayed multiple times on crowded city beaches, sleeping calm for hours just few meters away from humans.

[49] In the week of 22–28 April 2013, what is believed to have been a monk seal was viewed in Tyre, southern Lebanon; photographs have been reported among many local media.

[50] A study by the Italian Ministry of the Environment in 2013 confirmed the presence of monk seals in marine protected area in the Egadi Islands.

[57] On 10 April 2016, a monk seal was spotted and photographed by a group of foreign exchange students and local bio-engineers in a creek in Manavgat District in Turkey's southern Antalya Province.

[67] On 24 July 2021, a previously rescued and rehabilitated monk seal nicknamed "Kostis" was found dead in the waters of the Cycladic islands.

[69] On 12 May 2023, a healthy adult female monk seal was observed and photographed resting for at least a few hours on the beach in Jaffa near Tel Aviv, Israel.

International consultation assessed that she is in normal molt to shed her winter coat, mostly relaxing on the section of beach that has been fenced off for her, and occasionally going into the water.

[74] Damage inflicted on fishermen's nets and rare attacks on offshore fish farms in Turkey and Greece are known to have pushed local people towards hunting the Mediterranean monk seal, but mostly out of revenge, rather than population control.

[78] MOm is greatly involved in raising awareness in the general public, fundraising for the helping of the monk seal preservation cause, in Greece and wherever needed.

[79][80] The complex politics concerning the covert opposition of the Greek government towards the protection to the monk seals in the eastern Aegean in the late 1970s is described in a book by William Johnson.

According to Johnson, the Greek secret service, the YPEA, were against such moves and sabotaged the project to the detriment of both the seals and conservationists, who, unaware of such covert motivations, sought only to protect the species and its habitat.

The group has taken initiative in joint preservation efforts together with the Foça municipal officials, as well as phone, fax, and email hotlines for sightings.

The MoU covers four range States (Mauritania, Morocco, Portugal and Spain), all of which have signed, and aims at providing a legal and institutional framework for the implementation of the Action Plan for the Recovery of the Mediterranean Monk Seal in the Eastern Atlantic.

[87] In the 11th century BC, the Assyrian king Tiglath-Pileser I was gifted several animals by the Egyptian pharaoh Ramesses XI, including a crocodile and an unknown creature known as the "river-man".