, consuming large amount of plant matter. Pictured are grazing elephants from
Kerala, India Asian elephants are
crepuscular. Around 50 to 75% of the day is devoted to eating. They are generalist feeders, and are both
grazers and
browsers. They are known to feed on at least 112 different plant species, most commonly of the order
Malvales, as well as the
legume,
palm,
sedge and
true grass families. They browse more in the dry season with bark constituting a major part of their diet in the cool part of that season. They drink at least once a day and are never far from a permanent source of fresh water. Cows and calves move about together as groups, while bulls disperse from their mothers upon reaching adolescence. Bulls are solitary or form temporary "bachelor groups". Cow-calf units generally tend to be small, typically consisting of three adults (most likely related females) and their offspring. Larger groups of as many as 15 adult females have also been recorded. Seasonal aggregations of 17 individuals including calves and young adults have been observed in Sri Lanka's
Uda Walawe National Park. Until recently, Asian elephants, like African elephants, were thought to be under the leadership of older adult females, or
matriarchs. It is now recognized that cows form extensive and very fluid social networks, with varying degrees of associations between individuals. Social ties generally tend to be weaker than in African bush elephants. Elephants can distinguish low-amplitude sounds. Rarely,
tigers have been recorded attacking and killing calves, especially if the calves become separated from their mothers, stranded from their herd, or orphaned. Adults are largely invulnerable to natural predation. There is a singular anecdotal case of a mother Asian elephant allegedly being killed alongside her calf; however, this account is contestable. In 2011 and 2014, two instances were recorded of tigers successfully killing adult elephants; one by a single tiger in
Jim Corbett National Park on a 20-year-old young adult elephant cow, and another on a 28-year-old sick adult bull in
Kaziranga National Park further east, which was taken down and eaten by several tigers hunting cooperatively. Elephants appear to distinguish between the growls of larger predators like tigers and smaller predators like
leopards; they react to leopards less fearfully and more aggressively.
Reproduction Reproduction in Asian elephants can be attributed to the production and perception of signaling compounds called
pheromones. These signals are transmitted through various bodily fluids. They are commonly released in urine but in males they are also found in special secretions from the
temporal glands. Once integrated and perceived, these signals provide the receiver with information about the reproductive status of the sender. If both parties are ready to breed, reproductive ritualic behavior occurs and the process of sexual reproduction proceeds. Bulls will fight one another to get access to
oestrus cows. Strong fights over access to females are extremely rare. Bulls reach sexual maturity around the age of 12–15. Between the ages of 10 and 20 years, bulls undergo an annual phenomenon known as "
musth". This is a period where the
testosterone level is up to 100 times greater than non-musth periods, and they become aggressive. Secretions containing
pheromones occur during this period, from the paired temporal glands located on the head between the lateral edge of the eye and the base of the ear. The aggressive behaviors observed during musth can be attributed to varying amounts of
frontalin (1,5-dimethyl-6,8-dioxabicyclo[3.2.1]octane) throughout the maturation process of bulls. Frontalin is a
pheromone that was first isolated in bark beetles but can also be produced in the bulls of both Asian and African Elephants. The compound can be excreted through urine as well as through the temporal glands of the bull, allowing signaling to occur. During musth, increased concentrations of frontalin in the bull's urine communicate the reproductive status of the bull to female elephants. Similar to other mammals, hormone secretion in female elephants is regulated by an
estrous cycle. This cycle is regulated by surges in
Luteinizing hormone that are observed three weeks from each other. This type of estrous cycle has also been observed in African Elephants but is not known to affect other mammals. The first surge in Luteinizing hormone is not followed by the release of an egg from the ovaries. However, some female elephants still exhibit the expected mating protocols during this surge. Female elephants give ovulatory cues by utilizing sex
pheromones. A principal component thereof, (Z)-7-dodecen-1-yl acetate, has also been found to be a sex pheromone in numerous species of insects. In both insects and elephants, this chemical compound is used as an attractant to assist the mating process. In elephants, the chemical is secreted through urination and this aids in the attraction of bulls to mate. Once detected, the chemical stimulates the
vomeronasal organ of the bull, thus providing information on the maturity of the female. Reproductive signaling exchange between male and female elephants are transmitted through olfactory cues in bodily fluids. A bull that is ready to breed will move closer to the urine and in some cases an erection response is elicited. A bull that is not ready to breed will be timid and try to dissociate themselves from the signal. During this period, mother to calf communication primarily takes place through temporal means. However, male calves have been known to develop sex pheromone-producing organs at a young age. Early maturity of the vomeronasal organ allows immature elephants to produce and receive
pheromones. It is unlikely that the integration of these pheromones will result in a flehmen response in a calf. Female Asian elephants sexually mature around the age of 10~15 and keep growing until 30, while males fully mature at more than the age of 25, and constantly grow throughout their life. Average elephant
life expectancy is approximately 60 years.
Generation length of the Asian elephant is 22 years.
Intelligence Asian elephants have a very large and highly developed
neocortex, a trait also shared by
humans,
apes and certain
dolphin species. They have a greater volume of
cerebral cortex available for
cognitive processing than all other existing land animals. Results of studies indicate that Asian elephants have cognitive abilities for tool use and tool-making similar to
great apes. They exhibit a wide variety of behaviours, including those associated with
grief, learning,
allomothering,
mimicry, play,
altruism, use of
tools,
compassion,
cooperation,
self-awareness,
memory, and
language. Elephants reportedly head to safer ground during natural disasters like
tsunamis and earthquakes, but data from two satellite-collared Sri Lankan elephants indicate this may be untrue. Several students of elephant cognition and
neuroanatomy are convinced that Asian elephants are highly intelligent and self-aware. Others contest this view. ==Threats==