Tuesday, May 31, 2016

The Bats of Cuba

Bats inhabit nearly every landmass on the planet, with the exception of the arctic and Antarctica, reaching their maximum diversity in the tropics. Current tallies rank bat diversity at 202 genera and over a thousand species! (Simmons, 2005).

Bats are highly specialized mammals. Not only can they truly fly (meaning powered flight), but they use echolocation to navigate and detect prey while in flight. Echolocation is a way of navigation by echoes, which bats and other mammals like dolphins emit to sense their environment and find food. Some birds, like the oilbird Steatornis caripensis, uses echolocation, but at a level we can hear. In addition to their characteristic webbed wings, their eyesight is better in the dark than ours, demystifying their bad reputation of poor eyesight.

Leach's single leaf-nosed bat Monophyllus redmani (subspecies clinedaphus) a
pollen-nectar feeder Microchiropteran common to the Greater Antilles

Chiropterans are divided into two groups: the small echolocating bats or Microchiroptera, and the non-echolocating and much larger Megachiroptera. The giant bats portrayed in movies often represent the large fruit-eating Megachiropterans. They are not all vampire bats!    

Ecologically, bats play keystone roles in the consumption of insects, distribution of plant seeds, and pollination of plants. Other bats are carnivores, also helping maintain the ecological balance of the ecosystems they inhabit.

Bats are the most diverse mammals of the Cuban archipelago representing over 75% of Cuba's mammalian fauna! Of the 34 species of mammals recorded in Cuba, 26 are bats. Currently, these 26 species are classified into six main groups including the nose-leaf bats (phyllostomids), the funnel-eared bats (natalids), the fisher bulldog bat (noctilionid), the free-tailed mastiffs (molossids), the insectivorous ghost-faced bats (mormoopids) and the vespertilionids. The majority are well distributed within the main island of Cuba, the isle of Pines, and a few of the thousand keys that make up the archipelago (Silva, 1983; Mancina, 2011, 2012).

Waterhouse's leaf-nosed bat Macrotus waterhousei
and the Cuban fig-eating bat Phyllops falcactus digitally
drawn by biologist and bat specialist Dr. Adrian Tejedor from
field sketches of specimens captured in Pinar del Rio.

The Cuban archipelago is the largest of the Antillean islands. It is located in the Antillean subzone of the Neotropics where it enjoys a warm weather and abundant rainfall most of the year. The geological formation of the Caribbean islands provided an intricate and complex mosaic of calcium-rich rocks, such as limestone, so important to cave formation and varied soils. Altogether, these variables give rise to lush vegetation, which supported by the warm climate, incites Cuba's biodiversity, especially of bats.

The Cuban archipelago, in the Caribbean basin, as seen in Google Earth.

Geologically, Cuba has been available for bat colonization since the latest Eocene (MacPhee and Iturralde, 1994). This means that there have been somewhat permanent group of islands where Cuba is located today, at least for the last 35 million years, giving ample time for bats to reach it and evolve there.
In the Pliocene - 5 million years ago - the islands had their largest subaerial extent, and thus their largest landmass increase to date (Iturralde, 2010). This was followed by the multiple landmass fluctuations experienced during the Quaternary glaciations. During the last 800,000 years, the Cuban archipelago increased and decreased in size at least 20 times, with the glacial periods decreasing sea levels, and the interglacials increasing it. This is within a range of ~20 meters from the modern standard. In effect, this had substantial effects on the formation of karstic features, such as caves, that serve some bats as roosts, affected plant distribution, and likely also the distribution and evolution of bats in the island. But most importantly, it likely played a role on the total number of species the archipelago could sustain.

A lone Cuba fruit bat Artibeus jamaicensis parvipes in roost in Cueva Ambrosio,
Varadero, alongside Amerindian cave pictographs.

During the Quaternary, Cuba, and the Bahamas acted like a single archipelago. Today that archipelago is mostly drowned by higher sea levels. Increased sea levels likely flooded potential cave roosts affecting strict cave dwellers. There are bats that have adapted not only to live in caves but also preferring hotter environments within cave systems. Caves with hotter than normal chambers are called "hot caves" because the temperature in some of its rooms increases to above 40 degrees C with a relative humidity above 90 percent. These hot environment form in chambers with restricted access, in which large colonies of the bats roost. Their body heat, perspiration, urine and droppings, all within a very restricted and poorly ventilated cave room results in the abnormal increase in room temperature and humidity. Hot cave bats include the pollen-eater Phyllonycteris poeyi and Pteronotus quadridens.

The changes in world climate during the last 2 million years, or that Quaternary epoch that we've been referring to, brought changes in rainfall, temperatures, and potential land size, therefore potentially affecting different species. However, bats were not significantly culled by the Quaternary climatic fluctuations, as far as we can tell today from the fossil record, in comparison to other mammals groups, like monkeys and sloths, which disappeared completely. Cuba lost only three species during the last glacial maximum, ~18,000 years ago, as indicated by the fossil record of Cueva El Abron, in Pinar del Rio (see Suarez and Diaz-Franco, 2003; Balseiro, 2011). Others survived until a thousand years ago or less (Orihuela, 2012; Orihuela and Tejedor, 2012, Orihuela et al, in prep).

The greater bulldog bat Noctilio leporinus. This is Cuba's largest bat. It feeds mostly on fish,
but it has been observed eating insects near street lamps.

Cuban bats, like most bats, inhabit most ecosystems where they have evolved adaptations to many forms of feeding. There are bats that eat insects, seeds, fruits, nectar, pollen, and some that feed only on blood, such as the infamous vampire bats, or fish - as the Noctilio leporinus above. In the past, there were vampire bats in Cuba. Vampire bats are locally extinct in Cuba today, but their fossil remains suggest their presence on the main island up to several hundred years ago! (Suarez, 2005; Orihuela, 2011, 2012) (see my previous post on vampire bats here).

Thomas Horsfield on the right and John Edward Grey on the left.
Both men dedicated time to collecting and describing the first Cuban bats during the XIX century.

We owe the first published account on Cuban bats to Thomas Horsfield, who sent a letter to the prestigious Zoological Journal in 1828 while he resided in Cuba. Horsfield and the British naturalist William Sharp MacLeay sent specimens to the British museum. These specimens allowed John Edward Grey to properly describe the first species in 1840 in his article "Description of some Chiroptera discovered in Cuba", published in the Annals of the Natural History, volume IV (Silva, 1983).

The Antillean fruit-eating bat Brachyphylla cavernarum and the big free-tailed bat Nyctinomops macrotis
lithographs from Grey's first description of Cuban bats. These are also the first graphic depiction of any Cuban bat.
Lithographs made by the french J. Basire in 1839. B.cavernarum here is likely B. nana but nana was not properly
described until the early XX century.

Since then, and no doubt thanks to the efforts of many naturalists such as Johannes Gundlach in the XIX century and Gilberto Silva-Taboada of the XX, among others, the knowledge on the natural history of Cuban bats grew steadily. Their research quickly demonstrated the diversity of the Cuban bat fauna. There are more species in Cuba, with species representing most of the known New World groups, than in all the North American continent!

  Parnell's mustached bat Pteronotus parnelli from Nesofontes Cave near Matanza, Cuba.

The Cuban bat fauna is surrounded in interesting stories of accidental discoveries and rediscoveries. Such as it happened to the two bat specialists, the Cuban mastozoologist G. Silva-Taboada and Karl Koopman of the American Musem of Natural History (NY) while mistnetting bats in the Pan de Guajaibon, Pinar del Rio, in the 1950s. There they caught a living Cuban pallid bat Antrozous koopmani, the only one ever caught alive for decades. This is a species similar to the pallid bat Antrozous pallidus of the arid western U.S. The Cuban pallid was previously known from a handful of isolated skulls and two specimens preserved in spirits collected in the early decades of the XX century. The feat his yet to be repeated. Antrozous koopmani is today the rarest of Cuban bats, and is presumed nearly extinct (Mancina, 2012).

The list is followed by the greater funnel-eared bat Natalus primus, a critically endangered species known alive only from the single location of La Barca cave in Guanahacabibes, extreme western Cuba. There it was rediscovered by biologist Adrian Tejedor in 1991. Tejedor has written several interesting articles and a monograph on the rare and interesting funnel-eared bats (Natalids) of Cuba and the Caribbean (Tejedor, 2011 and citations therein). Cuba has other two funnel-eared bats. One of them, Nyctiellus lepidus, is one of the smallest bats in the world, known in Cuba as the "butterfly bat". The other, Chilonatalus macer, is similar to the Natalus major on the right of the image below but smaller.  Cuban natalids are all are endemic.

Left: Pteronotus quadridens from Hispaniola. Right: Hispaniolan funnel-eared bat
Natalus major from Cueva de Los Patos, also in Hispaniola.
These are small insectivores that live only in caves.

Other interesting records include Myotis sodalis, likely an errant from Florida found mummified by G. Silva in the city of Havana during the winter of 1966 (Silva, 1983). Eumops perotis, likely a vagrant or erroneous record dating back to 1839, a tree-dwelling Lasiurus insularis found by Ricardo Viera on the banks of the Yumuri River, Matanzas, in 2004, and our rediscovery of Desmodus rotundus in 2003; the fifth vampire bat fossil record from Cuba, among other informative, but isolated discoveries (Silva, 1983; Viera, 2004; Orihuela, 2010; Orihuela et al, in prep.). To this adds an array of new species and new deposits rich in bat fossils (Silva, 1974; Suarez, 2005; Suarez and Diaz-Franco, 2003; Mancina and Garcia, 2005; Jimenez et al., 2005; Balseriro, 2011; Orihuela, 2012).

Most of these latter species, however, are either accidental records, critically endangered, extirpated or extinct today. In addition to the extant 26 species, there are 8 disappeared species for a total of 34 known to have existed in Cuba at least during the last 20,000 years. The complex account of Cuban bat extinctions is reserved for an upcoming post; a topic most interesting to me, and the focus of most of my research.

Stay tuned!

The greater Cuban funnel-eared bat Natalus primus, severely endangered
and extant only in Cueva la Barca, Guanacahabibes, western Cuba.
Digital painting by, and copyright of Adrian Tejedor.


There are more citations, especially on area restriction, bat habitat, feeding, and climatic changes of the Quaternary that, if included, would have made this post a bit more tedious. I think, however, that the references below, in addition to the work of Angel Soto-Centeno, David Steadman, Danny Rojas and Liliana Davalos, will provide a good background for those interested in keeping up with this ever-growing body of literature.

Balseriro, F. 2011. Los murcielagos extinctos. pp: 171-177 en Borroto-Paez, R. y C. A. Mancina (eds) Mamiferos en Cuba. UPC print, Vaasa

Jiménez, O., M. M. Condis, and E. García. 2005. Vertebrados post-glaciales en un residuario fósil de Tyto alba scopoli (Aves: Tytonidae) en el occidente de Cuba. Revista Mexicana de Mastozoología, 9:84-111.

Koopman, K.F. 1958. A fossil vampire bat from Cuba. Breviora 90:1-4.

Suárez, W. 2005. Taxonomic Status of the Cuban Vampire Bat (Chiroptera: Phyllostomidae: Desmodontinae: Desmodus). Caribbean Journal of Science 41 (4):761-767.

Gonzalez, Alonso, et al. 2012. Libro Rojo de los Vertebrados de Cuba. Editorial Academia, La Habana. See "Mamiferos" pp:269-291 by mastozoologist Carlos Mancina.

Mancina, C. A., and L. Garcia. 2005. New genus and specis of fossil bat (Chiroptera:Phyllostomidae) from Cuba. Caribbean Journal of Science, 41: 22-27.

Mancina, C. A. 2011. Introduccion a los murcielagos pp: 123-133 en Borroto-Paez, R. y C. A. Mancina (eds) Mamiferos en Cuba. UPC print, Vaasa

Orihuela, J. 2011. Skull variation of the vampire bat Desmodus rotundus (Chiroptera: Phyllostomidae): Taxonomic implications for the Cuban fossil vampire bat Desmodus puntajudensisChiroptera Neotropical 17(1): 963-976.

Orihuela, J. 2012. Late Holocene fauna from a cave deposit in Western Cuba: post-Columbian occurrence of the vampire bat Desmodus rotundus (Phyllostomidae: Desmodontinae). Caribbean Journal of Science, 46 (2): 297-313.

Orihuela, J., and A. Tejedor. 2012. Peter's ghost-faced bat Mormoops megalophylla (Chiroptera: Mormoopidae) from a pre-Columbian archaeological deposit in Cuba. Acta Chiropterologica 14(1): 63-72.

Orihuela, J., R. Viera, and L. Vinola. 2017. New bat records based on modern and fossil remains from the province of Matanzas, Cuba.  

Silva Taboada, G. 1974. Fossil Chiroptera from cave deposits in Central Cuba, with a description of two new species, and the first record of Mormoops megalophylla. Acta Zoologica Cracoviensia, 19: 33-83.

Silva Taboada, G. 1983. Los Murcielagos de Cuba. Editorial Academia, La Habana.

Suarez, W. and S. Diaz-Franco. 2003. A new fossil bat (Chiroptera:Phyllostomidae) from a Quaternary cave deposit in Cuba. Caribbean Journal of Science, 39:371-377.

Tejedor, A. 2011. Systematics of the funnel-eared bats (Chiroptera: Natalidae). Bull. Amer. Mus. Nat. Hist. 353.

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