TATAKalikasan Series 7
The Tamaraw (Bubalus mindorensis)
- Nature's Example of Speciation*
Speciation is the evolutionary process by which populations
evolve to become distinct species.
Dr Abe V Rotor
Tamaraw in its natural habitat in Mindoro Island; skeleton of a tamaraw
at the Museum of Natural History, UPLB Mt Makiling Laguna
The Tamaraw (Bubalus mindorensis) or Mindoro Dwarf Buffalo is a small hoofed mammal belonging to the family Bovidae. It is endemic to the island of Mindoro in the Philippines and is the only endemic Philippine bovine. It is believed, however, to have once also thrived on the greater island of Luzon. The tamaraw was originally found all over Mindoro, from sea level up to the mountains (2000 meters above sea level), but because of human habitation, hunting, and logging, it is now restricted to only a few remote grassy plains and is now an endangered species.
Contrary to common belief and past classification, the tamaraw is not a subspecies of the local carabao, which is only slightly larger, or the common water buffalo. In contrast to the carabao, it has a number of distinguishing characteristics: it is slightly hairier, has light markings on its face, is not gregarious, and has shorter horns that are somewhat V-shaped. It is the largest native terrestrial mammal in the country.
To me this means that the carabao and tamaraw, though of different lineages, undoubtedly had a common ancestor, shared by other buffaloes found in Asia and in different parts of the world.
In the same manner plants and animal species evolved from common stocks, popularly referred to as missing links, named for the fact that it is rare and extremely difficult to determine where that crossroad of dichotomy lies.
When Charles Darwin found out that finches vary from island to island in the Galapagos group pf islands on the equatorial eastern coast of South America, he was in effect telling to the scientific community of an evolutionary phenomenon called speciation - the formation of species. Because it is a very slow and indeterminate at that, scientists were baffled by the question, "When does a species called a species, and not just a variety or breed?"
What I learned from my professor, the famous Deogracias Villadolid (PHOTO) who introduced tilapia in the Philippines in the fifties, is that, when the species in question is capable of interbreeding to make a population, and on the other hand, no longer capable of breeding with its original stock or parent species, or members of its former lineage. Dr Villadolid emphasized that this criterion is more reliable than morphological deviation, ecological distribution notwithstanding.
The tamaraw is no doubt a product of speciation. The island of Mindoro is its original home and still its natural habitat today, the forested areas and near open-canopied glades. Since human habitation and subsequent forest fragmentation its population has drastically declined to a few dozens. This is exactly the same situation the wild buffaloes of bisons of the Prairies face before they are saved from extinction in the last hour.
The tamaraw is a grazer that feeds on grasses and young bamboo shoots although it is known to prefer cogon (Imperata cylindrica) and talahib (Saccharum spontaneum). They are naturally diurnal, feeding during the daytime hours; however, daytime human activities have recently forced select B. mindorensis individuals to be nocturnal to avoid human contact.
The tamaraw is known to live for about 20 years, with an estimated lifespan of about 25. The adult female tamaraw gives birth to one offspring after a gestation period of about 300 days. There is an interbirth interval of two years, although one female has been sighted with three juveniles. The calf stays for 2–4 years with its mother before becoming independent.
Let's help conserve the highly endangered tamaraw, proudly our own endemically.
Speciation produces diversity of life on earth by splitting evolutionary lineages through the evolution of reproductive isolation between populations of a species. In ecological speciation, divergent natural selection to adapt to different environments results in the evolution of reproductive isolation.
Acknowledgement: Museum of Natural History UPLB, Marlo Rotor and Internet for the photos. and Wikipedia
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