The Mallorcan midwife toad (Alytes muletensis) is a unique amphibian found exclusively on the Balearic Island of Mallorca. Often called a “living fossil,” it was initially identified from fossil remains in 1977 before live specimens were discovered in 1979. This species represents an ancient amphibian lineage, having diverged from other groups approximately 155 million years ago.
The Midwife Breeding Strategy
The Mallorcan midwife toad exhibits a distinctive reproductive strategy, with the male playing a central role in parental care. During the breeding season, typically from May to June, the female lays 7 to 12 eggs. Following fertilization, the male carefully wraps these egg strings around his hind legs.
The male carries the developing eggs, providing an optimal environment for their growth and protecting them from predators. This continuous care continues for about three to four weeks, during which the eggs gradually darken as the larvae develop inside. When the tadpoles are ready to hatch, the male returns to a suitable water body, such as a stream or pool, and submerges himself, allowing the tadpoles to emerge.
The larval stage of the Mallorcan midwife toad is notably long, lasting anywhere from 6 to 18 months, depending on water temperature; cooler temperatures prolong development. These tadpoles can grow to an impressive length of up to 8 centimeters, making them among the largest amphibian larvae in Europe.
Where It Lives and What It Looks Like
The Mallorcan midwife toad inhabits the mountainous regions and gorges of the Serra de Tramuntana. These toads prefer environments with small streams deeply carved into limestone mountains, often seeking refuge in rock crevices and under stones. They also utilize permanent pools within these areas and can even be found in artificial water bodies near the gorges.
Adult Mallorcan midwife toads are relatively small, typically measuring between 3.5 to 4 centimeters in length, making them the smallest midwife toad species. Their body structure is somewhat frog-like, characterized by longer legs and fingers compared to other midwife toads. They possess a large, flattened head. The toads are primarily nocturnal, often heard calling during the breeding season rather than seen, with their calls described as resembling metal being hit with a hammer, which gives them their local name “Ferreret,” meaning “little metal worker” in Balearic Catalan and Spanish.
Rediscovery and Efforts to Protect It
The Mallorcan midwife toad was initially described from fossil remains in 1977, leading to the belief that the species had been extinct for over 2,000 years. However, living specimens were unexpectedly discovered in 1979 in the inaccessible limestone canyons of northern Mallorca, earning it the designation of a “Lazarus taxon.”
The species is currently listed as Endangered by the International Union for Conservation of Nature (IUCN), with an estimated wild population ranging from 500 to 1500 breeding pairs. Major threats include predation by introduced species like the Viperine Snake (Natrix maura) and competition for resources with the introduced Perez’s Frog (Rana perezi). Habitat degradation from tourism development, increased water demand, and recreational pressures also pose risks, potentially spreading diseases such as chytridiomycosis.
In response to these threats, a comprehensive recovery program was initiated in 1985, supported by the Mallorcan government, conservation organizations, and zoos. This program involved captive breeding, with the first animals taken from the wild in 1985 and successfully bred in terrariums. Reintroduction efforts began in 1989, releasing captive-bred toads and tadpoles into areas where the species had disappeared, significantly expanding its distribution by 100% and establishing twelve new breeding sites. While reintroductions were temporarily suspended due to the transmission of chytridiomycosis, ongoing efforts focus on mitigating disease and protecting the species through national and sub-national legislation, including its listing on Appendix II of the Bern Convention and Annexes II and IV of the EU Habitats Directive.