Fish-eating Bats (Myotis vivesi): Profile and Information

Fish-eating Bats

Bats are one of the most intriguing animals in the wild. Myotis vivesi, also known as the fish-eating bat or fish-eating myotis, is a species of bat that resides around the Gulf of California and eats fish and crustaceans.

The fish eating bat is the largest animal of the genus Myotis in the American continent. They have exceptionally large feet, which works as a major hunting tool.

This bat was first described in 1901 by Auguste Ménégaux and remained the only species in the subgenus (or genus) Pizonyx.

Scientific Classification

  • Kingdom: Animalia
  • Phylum: Chordata
  • Class: Mammalia
  • Order: Chiroptera
  • Family: Vespertilionidae
  • Genus: Myotis
  • Species: M. vivesi

Myotis vivesi is the most significant species in the genus Myotis in the American continent and has a similar size to the Eurasian Myotis myotis ( known as the greater mouse-eared bat). The skull of this bat averages 23 millimeters (0.91 in) in length.

The second most significant Myotis species in the New World, the Myotis velifer, owns a skull of 17.6 mm (0.69 in) long and has feet of 8 mm (0.31 in) long. The M. vivesi is known to have greatly elongated hind feet, which has an average of 23 mm (0.91 in) long.

Just like many other fish-eating bats, the Myotis vivesi own a pair of long, efficient wings, featuring high aspect ratio and low wing loading, and very large feet housing sharp claws.

The uropatagium (this is the wing surface between the bat’s hind legs) carries a fringe of silky fur of unknown function. However, the uropatagium itself is a tool for hunting.

The fur in the uropatagium is around 8 mm (0.31 in) in length and comes in a variety of colors from fawn to brown, with the root of each hair having a dark grey color. The same as other piscivorous species of Myotis, the M. vivesi has a pale underside.


Myotis vivesi can be found along the coasts of the Gulf of California, located in the Mexican states of Baja California, Sonora, and Baja California Sur, especially on small islands.

A tiny population of the fish-eating bats exists on the Pacific coast of the Baja California peninsula, between Punta Coyote and Isla Encantada.

Since the fish-eating bats live on small islands, their range is naturally fragmented, but data from the mtDNA control region and microsatellites indicate that there is no isolation by distance in these bats

Ecology and behavior

Myotis vivesi known as the fish-eating bats feed primarily on marine fish or crustaceans, as well as the squat lobster Pleuroncodes planipes.

Asides this bat, there is only one other bat species that hunt from the waters, which is the Noctilio leporinus. The guano that M. vivesi produces is red if it has fed on crustaceans, and it looks black if it has fed on fish; green guano and brown guano only result from eating algae and insects.

Asides feeding on fish and crustaceans, the M. vivesi also occasionally eats aerial insects. M. vivesi can easily cover vast distances when they hunt; in 1970, scientists discovered “a group of almost 400 M. vivesi around a boat at least 7 km [4.3 miles] off the shore”. M. vivesi lives in an arid environment and now can concentrate its pee; this allows them to survive by drinking seawater.

M. vivesi would rather roost either in a cave or under rocks exposed by landslides. These bats sometimes share their roosts with black petrels (Oceanodroma melania), and least petrels (Halocyptena microsoma).

Taxonomy and evolution

The first time Myotis vivesi was described by Auguste Ménégaux in 1901. Gerrit Smith Miller moved these species to a new genus, Pizonyx, in 1906, but that taxon is now included in the Myotis.

Ménégaux gave no hint of the etymology of the particular name vivesi; it may either refer to a person known as Vives or taken from the Latin verb Vivere, which means “to live.”

If Vives was an individual, he most definitely was not the collector of the specimens that was recorded as Léon Diguet.

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