When elephants experience sexual behaviors, they are experiencing a term called musth. Musth is when an adult male elephant reaches a stage of increased testosterone. Males first enter this at the age of 15, but it is not intense or desirable until over the age of 25. Younger male elephants seem to enter this state during the dry seasons (Jan-May), while older elephants experiencing this during wet seasons (Jun-Dec). You can tell a male is in musth by a secretion coming out of their temporal gland, which runs down the side of the face. You often will see a wet mark right behind the eyes, dripping all the way down. He may urinate with his penis still in his sheath, which causes the urine to spray on his hind legs. Behaviors associated with musth include: walking with the head held high and swinging, picking at the ground with the tusks, marking, rumbling and waving only one ear at a time. Musth can last from a day to four months.
Males become very aggressive during this time period (size definitely does matter!). Males are allowed to have more than one mating partner at a time. Males will sense that the females are ready to have sex due to the secretions and smells they give out in their urine. The male will asses the females condition by preforming a "flehmen response," in which he takes his trunk and scoops up a chemical sample and smells it. The oestrous cycle for a female lasts about 14-16 weeks. While most mammals have one surge of luteinizing hormone during the follicular phase, elephants have two. The first (or anovulatory) surge, could signal to males that the female is in oestrus by changing her scent, but ovulation does not occur until the second (or ovulatory) surge. Females fertility rate starts to go down at the age of 45-50 years old (like humans!).
Males begin to "mate guard," which means they protect the female who is ready to have sex from other males in musth. Females seek an older guardian in particular. For younger females, an approach by an older male is intimidating. Many times you will see the females family near by to make sure she is okay and for support. During intercourse, the male lays his trunk across the back of the female. It lasts about 45 seconds, (ouch!) and is very easy.
FUN FACT: Homosexuality is seen in elephants as well. Male elephants are seen stimulating each other during "play fights." Female elephants have been documented masturbating one another in captivity with their trunks.
Elephants go through the longest land-animal pregnancy, lasting about 22 months. Births tend to take place during the wet seasons. Calves are born about 85 cm or 33 in, and weigh about 260 lbs. Typically only one single elephant is birthed at a time, but there have been records of twins. Newborn elephants are quickly able to stand and walk to follow their mother and family herd. A new calf is usually the center of attention for herd members. Adults and most of the other young will gather around the newborn, touching and caressing it with their trunks. For the first few days, the mother is intolerant of other herd members near her young. If a predator nears the group, the family puts the new calves in the center and all stand around them. Nursing can begin within the first hour of birth. For the first three months, the new calves rely heavily on the mother for support and food. By nine months, mouth, trunk and foot coordination is perfected. After a year, a calf's abilities to groom, drink, and feed itself are fully developed. It still needs its mother for nutrition and protection from predators for at least another year. Suckling bouts tend to last 2-4 min/hr for a calf younger than a year and it continues to suckle until it reaches three years of age or older.