Elephas maximus

Geographic Range

Historically, Elephas maximus had a geographic range of 9 million square kilometers across a large part of Asia. This range extended as far west as current day Iraq, as far north as the Yangtze River in China, and across the Indian subcontinent and Southeast Asia, including the islands of Sri Lanka and Sumatra (Indonesia). The current geographic range is 500,000 square kilometers, which is only about 5% of the historical range. This range consists of small discontinuous areas in the Indian subcontinent and Southeast Asia.

• Biogeographic Regions
• oriental oriental
  • native native

Habitat

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.

• Habitat Regions
• tropical tropical
• terrestrial terrestrial

• Terrestrial Biomes
• savanna or grassland savanna or grassland
• forest forest
• rainforest rainforest
• scrub forest scrub forest

Physical Description

Elephas maximus 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 ( 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.

There are several differences between Asian elephants (genus Elephas ) and African elephants (genus Loxodonta ), which is the only other genus of elephants still alive. Elephas maximus 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. Elephas maximus 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. Elephas maximus has a flat back while Loxodonta have a sloping back. As a result, the head is the highest part of the body in E. maximus , while the shoulders are the highest in Loxodonta . Only male Asian elephants bear tusks while both male and female African elephants have tusks.

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 Elephas maximus in Borneo may be a distinct subspecies.

• Other Physical Features
• endothermic endothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• male larger
• ornamentation ornamentation

Reproduction

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.

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.

• Mating System
• polygynous polygynous
• cooperative breeder cooperative breeder

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.

• Key Reproductive Features
• iteroparous iteroparous
• year-round breeding year-round breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• viviparous viviparous

Females provide a high level of parental care for their offspring while males provide no parental care. Elephas maximus display allomothering, where individuals other than the parents provide care. Females that are usually related to the mother help provide care for the calves. Females suckle their calves frequently until about 2 years of age and continue suckling less frequently until 4 years of age. Females provide protection for their young offspring. Calves are usually located in very close proximity to their mother. They are also located near the center of the group to protect them from predators. When they are in trouble, a juvenile will make a distress call and the mother and other female elephants will respond quickly. The mother provides comfort to the calf using tactile behavior such as rubbing or touching. The calf learns how to obtain food, and how to communicate from its mother and other caretakers.

• Parental Investment
• precocial precocial
• female parental care female parental care
• pre-weaning/fledging
  • provisioning
    • female
  • protecting
    • female
• pre-independence
  • protecting
    • female
• post-independence association with parents
• extended period of juvenile learning

Lifespan/Longevity

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. Elephas maximus 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.

Behavior

Elephas maximus is a nomadic species that lives on the ground and moves around frequently. Their fastest speed is approximately 32 km/hour. They can climb hills easily, but are not able to jump. Elephants are very good swimmers, and can submerge their body leaving only the trunk out of the water. Elephas maximus is diurnal and nocturnal because of the amount of time needed to spend searching for food to sustain their large bodies. They spend 12 to 18 hours searching for and eating food, and eat 10% of their body mass daily.

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.

Elephas maximus has matriarchal social organization. The females and offspring live together in a group, while the males live in smaller groups or alone. A clan consists of related females and their offspring with strong social bonds, and is usually between 5 and 20 individuals in size. Larger groups are formed when clans loosely join together. These groups form and break apart depending on the season, habitat, and other conditions. After males reach sexual maturity they leave the group to live solitary or in small groups with other males with loose social bonds. Males are found with the larger groups when they are trying to mate with a female. There is combat and a dominance hierarchy for males that affects their ability to mate.

• Key Behaviors
• terricolous
• diurnal diurnal
• nocturnal nocturnal
• motile motile
• nomadic nomadic
• solitary solitary
• social social
• dominance hierarchies dominance hierarchies

Home Range

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.

Communication and Perception

Elephas maximus communicates with sound, visual signals, chemical signals, and touch. The trunk is important in these types of communication. The elephant can make many types of vocalizations that can travel both long and short distances. They are able to make vocalize in the infrasound range, which has a lower frequency than what humans can hear. Chemicals are secreted by temporal gland, in urine and feces, and exhaled that can be used for communication and reproduction. Chemical signals indicate if an individual is in musth or estrus, so these signals are important for finding mates for both females and males.

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.

• Communication Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

• Other Communication Modes
• pheromones pheromones
• scent marks scent marks

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• vibrations vibrations
• chemical chemical

Food Habits

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.

• Primary Diet
• herbivore herbivore
  • folivore folivore

• Plant Foods
• leaves
• roots and tubers
• wood, bark, or stems
• seeds, grains, and nuts
• fruit
• flowers

Predation

The only predators of Elephas maximus are Bengal tigers ( 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.

Ecosystem Roles

Elephas maximus is considered a keystone species because of their large impact on the ecosystem. They eat a very large amount of food daily, which facilitates nutrient cycling. Because of their large size, they transform the habitat by tearing down trees. This creates gaps in the forest, allowing small animals to move around. This space also allows for the growth of herbaceous plants, which are food for small animals.

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. Elephas maximus 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 E. maximus are mostly nematodes and parasitic worms.

• Ecosystem Impact
• disperses seeds
• creates habitat
• keystone species keystone species

Economic Importance for Humans: Positive

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.

• Positive Impacts
• body parts are source of valuable material
• ecotourism ecotourism
• research and education

Economic Importance for Humans: Negative

Elephas maximus has a negative effect on humans because they can ravage crop fields and kill people. There are 200 people killed by elephants yearly in India, and 50 killed yearly in Sri Lanka. They cause millions of dollars of damage to many different types of crops.

• Negative Impacts
• injures humans
• crop pest

Conservation Status

Elephas maximus is listed as Endangered on the IUCN Red List. The subspecies Elephas maximus sumatranus is Critically Endangered. Asian Elephants are included as Endangered on The US Federal list. Elephas Maximus is listed under Appendix I in CITES, with the most endangered species. The population of E. maximus is estimated to be 38,500 to 52,500, with 16,000 in captivity.

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.

Other Comments

Asian Elephants are described as being highly intelligent. The size of their brain is fairly large, indicating they most likely have good cognitive abilities. Elephas maximus are known for using tools for body care, feeding and drinking, rest and sleep, social behavior, and interspecific interactions.

Additional Links

Encyclopedia of Life

Contributors

Nikitha Karkala (author), The College of New Jersey, Matthew Wund (editor), The College of New Jersey, Tanya Dewey (editor), University of Michigan-Ann Arbor.

References

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