Primate Pronouncements

You've probably seen primates in zoos or on television or even online, but do you know what they sound like?  And if you've heard them, do you know why they are vocalizing?  Here are some examples of primate vocalizations along with what it is they are 'saying'.

Orangutans - "Male orangutans exhibit a curious and little-understood case of “bimaturism,” also referred to as “arrested development.” This means that there are two “types” of mature male orangutans: flanged and unflanged males. A flanged male has big cheek pads on the sides of his face and a large pendulous throat sack under his chin. An unflanged male has neither of these traits, and his body is usually smaller. Unflanged males are sexually mature and fully able to father offspring; females, however, seem to prefer to mate with the flanged males. Because of this, unflanged males often resort to “forceful copulation” in order to attain matings. Meanwhile, flanged males emit loud booming “long calls’, presumably to attract receptive females as well as to let other males know their whereabouts. It is not fully understood exactly when and why a mature male undergoes the transformation from unflanged to flanged, or even if every male undergoes this transformation (although it seems likely that he does eventually). It has been hypothesized that the existence of a dominant flanged male within the sensory range of an unflanged male inhibits the unflanged male’s development (by stimulating release of special hormones?). Thus, not until the dominant flanged male dies, moves away, or is defeated, or the subadult male himself moves away or stays low, can the unflanged male develop his cheek pads and large size."  from the Orangutan Foundation International.

Orangutan long call



Chimpanzee

"Dr. Jane Goodall’s long-term study of chimpanzee behavior at Gombe National Park helped scientists understand more about the diversity and meaning of chimpanzee calls. There are two types of chimpanzee calls:

Intraparty Calls – These calls take place between chimpanzees that are in the same group.

Distance Calls – These calls are made between groups that are separated, sometimes by a great distance.

One of the chimpanzee calls is the “pant-hoot.” Each individual chimpanzee has his or her own distinct pant-hoot. This helps other chimpanzees tell who is making the call even if they can’t see who is calling."  from the Jane Goodall Institute.

"High-ranking adult males pant-hoot most frequently. Females sometimes produce pant-hoots on their own and often join in a chorus of pant-hoots when others are calling. Chimpanzees pant-hoot in a variety of circumstances, such as arriving at fruit trees, responding to distant pant-hoots, when joining other community members, and when traveling."  Michael L. Wilson

Chimp pant-hoot



Gorilla

Gorillas are known for beating their chest, although to be honest it really doesn't sound too intimidating to humans.  It sounds more like they are trying to imitate the sounds of horse hooves..  "This behavior is done by all gorillas and the either one or two open-fist hands are clapped against the chest (Estes, 1991). Adult males produce a sound when doing this because of air sacs they have which are located on both sides of their throat (Estes, 1991). For the adult male this is a threat display (Estes, 1991)."  from Primates.com



A gorilla roar is much more impressive.



Gorillas have many types of vocalizations.  For more information, click here.


Gibbons

Gibbons probably have the most impressive voices.  When visiting the Denver Zoo, the gibbons were always the ones you could hear in most places in the entire zoo.  "All species of gibbons are known to produce elaborate, species-specific and sex-specific patterns of vocalisation often referred to as "songs" (Haimoff, 1984; Marshall & Marshall, 1976). Songs are loud and complex and are mainly uttered at specifically established times of day. In most species, mated pairs may characteristically combine their songs in a relatively rigid pattern to produce coordinated duet songs. Several functions have been attributed to gibbon songs, most of which emphasise a role in territorial advertisement, mate attraction and maintenance of pair and family bonds (Geissmann, 1999; Geissmann & Orgeldinger, 2000; Haimoff, 1984; Leighton, 1987)."  from the Gibbon Research Lab.

Gibbons singing??



Impressive or annoying??!!