Asian elephants live in a variety of habitats in the tropical region, including grasslands, tropical evergreen forests, moist deciduous forests, and scrub forests. They typically live in elevations from sea level to 3,000 meters, but elephants that live near the Himalaya Mountains sometimes move up higher than this range in hot weather. (Choudhary, et al., 2008; Daniel, 1998; Sukumar, 2003)
Elephantidae). There is a large degree of sexual dimorphism in elephants. The males are much larger than the females. Males have a height of 240 to 300 cm with a body mass of 3,500 to 6,000 kg. Females are 195 to 240 cm in height with a body mass of 2,000 to 3,500 kg. Males have tusks which are an elongation of the second upper incisors, while females lack tusks. (Daniel, 1998; Kurt and Garai, 2007; Nowak, 1999; Sukumar, 2003; Sukumar, 2006)is one of the largest terrestrial organisms and is considered a megafauna species. Asian elephants have gray skin that is covered with hair. In adults, this hair is sparse, while calves have thicker brown hair. The body length ranges from 550 to 640 cm. The trunk is a distinctive feature of the elephant family (
There are several differences between Asian elephants (genus Elephas) and African elephants (genus Loxodonta), which is the only other genus of elephants still alive. has a smaller size compared to Loxodonta. Asian elephants have one fingerlike projection at the tip of the trunk, differing from African elephants (Loxodonta), which have two fingerlike projections. has large flat ears, but they are smaller than the ears of Loxodonta. Asian elephants have four hooves on the hind foot while African elephants have only three hooves. has a flat back while Loxodonta have a sloping back. As a result, the head is the highest part of the body in , while the shoulders are the highest in Loxodonta. Only male Asian elephants bear tusks while both male and female African elephants have tusks. (Nowak, 1999; Sukumar, 2003)
There are three subspecies recognized: Elephas maximus maximus in Sri Lanka, Elephas maximus indicus in the Asian mainland, and Elephas maximus sumatranus in Sumatra (Indonesia). Elephas maximus maximus is different from the other subspecies because 90 to 95 percent of males lack tusks. There are varying views regarding which groups should be considered different subspecies. Based on DNA analyses, E. m. maximus and E. m. indicus may be part of the same group, while the population of (Sukumar, 2003; Sukumar, 2006)in Borneo may be a distinct subspecies.
Asian elephants are polygynous. There is male-male competition and female selection, so not all sexually mature males will be able to breed. The estrous cycle affects when females are able to breed. The cycle is 14 to 16 weeks long, and females are in estrus for 3 to 7 days. A female in estrus is fertile and receptive to mating with males in musth (see below). Females use auditory, visual, and chemical signals to indicate to males that they are in estrus. The female is required to cooperate for breeding to occur, so they will only allow the strongest and most fit males to mate with them. (Sukumar, 2003; Sukumar, 2006)
In male Asian elephants, mating is driven by a condition called musth. Males become aggressive towards other males and there is increased sexual behavior. Asian elephants have a temporal skin gland in their temples that is periodically active. During musth, the temporal gland and the testes become extremely enlarged. There is a strong smelling secretion of the temporal gland, which the male smears over his face and body using his trunk. Levels of testosterone, as well as other hormones, are elevated. There is increased chemical signaling and olfactory marking. Elephants in musth want to mate with females that are in estrous, meaning that they are fertile. Males have an increased level of aggression and physically fight with each other to compete for mates. They use their tusks in combat, and can become injured or be killed during these fights. Males in musth usually win fights over males that are not in musth, so musth is important in the reproductive success of males. Males need to be in good condition and eat an increased amount of food to be able to undergo musth. Females can detect signals to determine if a male is in musth. Females prefer mates in musth because it indicates that they are the most dominant and strongest mates. Younger males that have just reached sexual maturity typically cannot breed yet, because their musth is too weak and they cannot defeat older males. As a male becomes older, the musth gains intensity and the male will be able to breed starting around age 20. Musth is yearly and asynchronous, occurring at varying times of the year for different males. (Daniel, 1998; Kurt and Garai, 2007; Sukumar, 2003; Sukumar, 2006)
Asian elephants breed every 4 to 5 years. This breeding interval occurs because suckling the offspring delays the onset of estrus for about 2 years after birth, so the female is not fertile. Mating occurs year round, but in environments where there is seasonal rain, there is more breeding during the times of peak rainfall. This is most likely related to the increased availability of food during the rainy season. Normally a female gives birth to one offspring each breeding season. Twins are possible but very rare. The gestation period is usually 18 to 23 weeks. The average birth mass is 100 kg. Nursing is not required for survival after 2 years of age, but weaning does not occur until about 4 years of age. The typical age of independence is 5 years. Females usually become sexually mature at 10 to 15 years old, but this can vary greatly depending on the environment. Elephants that live in zoos can be obese and as a result, become sexually mature as early as 7 years old. Elephants that are captive and used for heavy labor are physically stressed and may not be sexually mature until age 22. In general, well-nourished individuals become sexually active at an earlier age. Males become sexually active at around the same age as females, 10 to 15 years old. (Choudhary, et al., 2008; Daniel, 1998; Mumby, et al., 2013; Sukumar, 2003; Sukumar, 2006)
The Asian elephant with the longest known lifespan was a male in a zoo that lived to be 86 years old. The longest known lifespan in the wild is not known because of the difficulty of estimating the age of adult elephants. It is expected that the longest lifespan in the wild is similar to the longest lifespan in captivity. The expected lifespan is about 60 to 70 years for both in the wild and in captivity. Tooth wear limits the lifespan in Asian elephants. The plant food that they eat causes wear on the teeth. (Choudhary, et al., 2008; Sukumar, 2003; Wiese and Willis, 2004)has multiple sets of molars that push out and replace the teeth as they are worn out. There is a set number of molars, so when all of the teeth are pushed out and worn down, the elephant cannot eat food and will die. The mortality rate for elephants between 5 and 40 years old is about 3% per year. The death rate for males is higher than the death rate for females. This is because males can be killed while fighting and competing with other males. Also, males may not be as fit as females, because of the higher metabolic costs associated with musth.
The Asian elephant has several behaviors related to thermoregulation. They live in a hot climate and have a large body size, which causes the elephants to heat up quickly. During the hottest hours of the day, they are less active and spend time in shady areas. Asian elephants bathe frequently and submerge themselves in water to cool down. They can use their trunk to spray water or saliva on themselves. They cover themselves in mud or soil to keep their skin cool. Asian elephants flap their ear to get rid of excess heat. This works because the large surface area of the ears allows heat to be lost quickly. There is a positive correlation between the frequency of ear flapping and the temperature of the environment. (Daniel, 1998; Kurt and Garai, 2007)
The size of the home range greatly varies from 20 square kilometers to 1,000 square kilometers. The size depends on the availability of food and water, as well as the proximity to human settlements. (Daniel, 1998; Sukumar, 2006)
Asian elephants can perceive visual, tactile, acoustic, and chemical signals. Their vision is relatively weak, but visual signals are still important in communication. Olfaction is also important for Asian elephants. They have a very strong sense of smell and use their trunk to reach out and smell things. They have a vomeronasal organ that can detect pheromones and other chemical signals. They use their trunk to bring a chemical signal to their vomeronasal organ. The trunk is also used for tactile perception. The tip of the trunk is very sensitive because there many free nerve endings and hair on the dorsal trunk tip which help with sensation. The trunk can be used to detect ground vibrations as well as obtaining information about an object it is touching. (Daniel, 1998; Kurt and Garai, 2007; Sukumar, 2003)
Asian elephants are herbivores that eat many types of plant food. Most of its diet consists of Fabaceae (legumes), Poaceae (grasses), Cyperaceae (sedges), Palmae (palms), Euphorbiaceae (spurges), Rhamnaceae (buckthorn) and Malvales (mallows, sterculias and basswoods). However, they can eat more than 100 species of plants, including bamboo, sugarcane, crops, roots of trees, flowers, fruit, seeds, grains, and the bark of trees. The trunk is important for the diversity of food habits in the elephant because it allows the elephant to grasp many types of food. (Daniel, 1998; Sukumar, 2003; Sukumar, 2006)
The only predators of Panthera tigris), which attack calves. Adult elephants are very large and have tusks making it dangerous for predators to attack. To avoid predation, younger elephants stay towards the center of a group, which provides protection. (Daniel, 1998; Kurt and Garai, 2007; Sukumar, 2003)are Bengal tigers (
Asian elephants are mutualists with some types of seed plants. The elephants eat the seeds as food. Once they are done digesting them, they will be dropped with the feces a large distance away from the original location, helping with seed dispersal. (Sukumar, 2003; Sukumar, 2006)also has a mutualistic relationship with the microbes in their digestive system. The microbes help digest the plant food that the elephant eats. The major parasites of are mostly nematodes and parasitic worms.
In the past, Asian elephants were used in armies to transport supplies and troops across the dense forest habitat. They were also hunted for ivory and their hide. Currently, they are mainly used for to provide power in forestry and logging, religious purposes, ecotourism, and education. (Kurt and Garai, 2007; Sukumar, 2003)
The greatest threats to E.maximus include loss and fragmentation of habitat, human-elephant conflicts, and poaching. Asian elephants are being affected by the loss of their natural habitat due to the expanding human population. Poaching male elephants for their tusks is another major issue affecting E.maximus. Since only males have tusks, poaching leads to extremely skewed sex ratios, creating a problem with inbreeding since there aren't enough breeding males. The elephants are also hunted for hide and meat. Poor elephant management in captivity is also a major issue. Asian elephants are sometimes chained and kept separately. This is a problem because elephants are very social, so they will be negatively affected. Another problem is that elephants rarely reproduce in captivity. Since there are so many elephants in captivity, this makes it difficult for the population size to increase. To help the species recover, poaching for ivory has been banned, and there have been measures taken to conserve the habitat of the Asian elephants. The population is still currently decreasing, but these actions have slowed the decline in the population. (Sukumar, 2003; Sukumar, 2006)
Asian Elephants are described as being highly intelligent. The size of their brain is fairly large, indicating they most likely have good cognitive abilities. (Kurt and Garai, 2007)are known for using tools for body care, feeding and drinking, rest and sleep, social behavior, and interspecific interactions.
Nikitha Karkala (author), The College of New Jersey, Matthew Wund (editor), The College of New Jersey, Tanya Dewey (editor), University of Michigan-Ann Arbor.
uses sound to communicate
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
uses smells or other chemicals to communicate
helpers provide assistance in raising young that are not their own
ranking system or pecking order among members of a long-term social group, where dominance status affects access to resources or mates
humans benefit economically by promoting tourism that focuses on the appreciation of natural areas or animals. Ecotourism implies that there are existing programs that profit from the appreciation of natural areas or animals.
animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.
parental care is carried out by females
an animal that mainly eats leaves.
forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
An animal that eats mainly plants or parts of plants.
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
a species whose presence or absence strongly affects populations of other species in that area such that the extirpation of the keystone species in an area will result in the ultimate extirpation of many more species in that area (Example: sea otter).
having the capacity to move from one place to another.
the area in which the animal is naturally found, the region in which it is endemic.
active during the night
generally wanders from place to place, usually within a well-defined range.
found in the oriental region of the world. In other words, India and southeast Asia.
chemicals released into air or water that are detected by and responded to by other animals of the same species
having more than one female as a mate at one time
rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.
communicates by producing scents from special gland(s) and placing them on a surface whether others can smell or taste them
scrub forests develop in areas that experience dry seasons.
reproduction that includes combining the genetic contribution of two individuals, a male and a female
one of the sexes (usually males) has special physical structures used in courting the other sex or fighting the same sex. For example: antlers, elongated tails, special spurs.
associates with others of its species; forms social groups.
uses touch to communicate
Living on the ground.
the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.
A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.
A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.
A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.
movements of a hard surface that are produced by animals as signals to others
uses sight to communicate
reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.
breeding takes place throughout the year
young are relatively well-developed when born
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