Madagascar started breaking off from mainland Africa some 200 million years ago, and before the arrival of more highly adapted monkeys, lemurs had few mammalian competitors. It is thought that lemurs arrived on the island via rafts of vegetation carried there by ocean currents. They survived the trip, and survived well. Their intelligent and aggressive nature allowed them to flourish, and they adapted quickly to the unique Madagascar environment.
Though “lemur” was initially meant to refer to slender loris, it is now exclusively used to describe the Malagasy primate. The term comes from the Latin word “lemures,” referring to ghosts that were exorcised during the Lemuria festival of ancient Rome.
The wide range of lemur species include primates on both ends of the scale. The smallest, known as Madame Berthe’s mouse lemur, weighs 30 grams (1.1 ounces), while the largest, the Indri or Diademed Sifaka species, is seven to nine kilograms (15-20 pounds). The extinct giant sloth lemur, however, could reach sizes similar to that of a gorilla — up to 160-to-200 kilograms (350 to 440 pounds).
When “upper primates,” (humans), arrived on Madagascar 2,000 years ago after learning how to navigate the high seas, habitat destruction and hunting greatly reduced the number of lemur species on the island. The largest species suffered the most due to their high meat yield. Most are extinct.
As Madagascar is the only place in the world to study lemurs, it has earned one of the four region delineations for primatology. The other regions are all of South and Central America; all of Southern and Southeast Asia; and mainland Africa. While Madagascar is one of 92 countries with wild primate populations, it alone is responsible for 21 percent of all primate genera and 36 percent of all primate families.
Though many species are extinct, scientists predict that between 10 and 20 new species of lemur will be discovered on Madagascar throughout the next generation. There are 60 “taxa” of lemur at the moment, including species, sub-species, and populations from 33 different species, five families, and 14 genera.
Of the 103 known species of lemur, 90 percent are categorized as either endangered, critically endangered, or threatened. Several species are on the brink of extinction, and others are already considered extinct.
Madagascar has wildly different wet and dry seasons, which forced lemur adaptations that include seasonal fat storage, small group sizes, day-and-night activity (known as cathmerality), and strict breeding seasons. The breeding seasons are responsible for female social dominance — male-male competition is high during seasonal breeding when resources are extremely limited.
The long snouts of lemurs are key for helping the animals to sift smells, but lemurs’ sense of smell is far more important than just sniffing out food. As they are less visually oriented than higher primates, lemurs use scent glands located on their wrists, inside their elbows, genital regions, and necks to leave scent marks for their groups, as well as urine or pheromones transferred by their wet noses.
The dry season in Madagascar means scarce resources, and lemurs have developed biological and societal coping mechanisms. To maximize energy, they can lower their metabolic rate to 20 percent lower than the values predicted for mammals of similar body mass. They’ve also adopted sunning behaviors, hunched sitting, group huddling and nest sharing to reduce heat loss.
