Odd One Out Part 2: More Quirky Questions

By Sophie Wasserman

Round Two of more interesting question from some creative thinkers! (see part one here: link)

"Do elephants really have the longest gestational period?"

Boonjan's baby body

One young student was quick to school us on extreme animal facts: though elephants have longest gestational period of any mammal (18-24 months), he pointed out that the record for longest of any animal actually goes to the frilled shark. Frilled sharks are ovoviviparous, or they lay eggs inside their bodies such that the embryos develop in a uterus, but get their nutrients from the yolk of the egg sac. The frill shark’s record is 3.5 years of pregnancy! Other runner-ups for the title include the black alpine salamander (2-3 years) and orcas (17 months). On the opposite end of the spectrum, some species of opossums give birth after only 12-14 days!

"Do elephants get their period?"

Thangmo won't become sexually mature until around 12-15
By Lisa Barrett

Elephants do not have a menstrual cycle and thus do not get their “period;" instead, their reproductive system is regulated by an estrous cycle. The cycle lasts about 15-17 weeks, so elephants go into “heat” (become sexually receptive) every 112 days, or only 3 times a year.  Usually this lasts for 1-3 days, during which the female will make particular vocalizations, assume different postures and ways of walking, and show increased interest in nearby bulls to signal her fertility. Just as in humans, her body is preparing her uterus for the possibility of pregnancy by creating a nutrient rich lining (called an endometrium) to support the potential embryo. If the elephant does not conceive during those few days she is receptive to breeding, rather than shedding the prepared lining as occurs in menstruation, her body reabsorbs and reorganizes the endometrium for later use.

"Are elephants the same as water buffalo?"

Asian water buffalo
Via Flickr Creative Commons

            This question came from one of our younger explorers, who was still surprised upon learning that elephant were closely related to sea cows and rock hyraxes. As you may expect, elephants are not the same as water buffalo, but they do have some traits in common. Both Asian elephants and the domestic Asian water buffalo (Bubalus bubalis) are mammals, meaning they are warm blooded, hairy animals who nurse their young, as well as both being herbivores, eating only plants to survive. Elephants and water buffalo are also both ungulates: if you look at their bone structure, they are walking on the tips of their toes. Both species can be found throughout Southeast Asia, and, most importantly, both love playing in the mud to cool off.

"Do elephants cry?"

Moisture flowing from elephant eye

Via Flickr Creative Commons

Though there is some evidence that elephants mourn their dead (read more in our previous blog here), the idea that elephants cry because of overwhelming emotions or stress has never been substantiated. It is not uncommon, however, to see trails of moisture running from the eyes of an elephant and these “tear tracks” are often misinterpreted and mislabeled. Elephants lack tear ducts; any moisture generated to lubricate the eye or remove irritants like dust naturally spills over onto the face. When the moisture is excessive, flowing into the elephant’s mouth for example, this can indicate some sort of ulcer or infection in the eye, and should be examined by a veterinarian. Otherwise, this phenomenon is perfectly natural and doesn't indicate any emotional or physical problems.

With all of the recent research demonstrating how intellectually and emotionally complex elephants can be, it’s understandable that people are quick to attribute even more “human-like” qualities to them. This question serves as an excellent reminder that we need to be aware of our own biases and perspectives when studying animal behavior. Take chimpanzees for example: an open-mouthed, top-teeth baring smile, which to us means joy and affection, is actually called a “fear grimace” in chimps and is used when an animal is afraid or trying to intimidate others. We cannot assume that because a behavior looks similar to ours, such as elephants “crying” or chimps “smiling”, that it is prompted by the same motivations as our own actions. Just as a traveler tries to understand the customs of a foreign country, research into animal behavior and communication becomes essential if we want to promote positive interactions between humans and our non-verbal neighbors.

References:

Kuhle, B. X. (2007). An evolutionary perspective on the origin and ontogeny of menopause. Maturitas, 57(4), 329-337.

McComb, K., Shannon, G., Sayialel, K. N., & Moss, C. (2014). Elephants can determine ethnicity, gender, and age from acoustic cues in human voices. Proceedings of the National Academy of Sciences, 201321543.

Ward, E. J., Parsons, K., Holmes, E. E., Balcomb III, K. C., Ford, J. K., Altenburger, A., ... & Gunz, P. (2009). The role of menopause and reproductive senescence in a long-lived social mammal. Frontiers in zoology, 6(4).

http://www.abc.net.au/science/articles/2013/10/28/3874904.htm

http://www.elephanttag.org/General/general_elephant_reproduction.html

http://www.mnn.com/earth-matters/animals/photos/12-animals-with-the-longest-gestation-period/

Photos

Asian Elephant by Will Harford via Flickr Creative Commons
Asian Water Buffalo Bubalus bubalis by Bernard Dupont via Flickr Creative Commons