Wordless Wednesday

Interspecies grooming at The Bronx Zoo

Interspecies grooming between Bonnet macaques (Macaca radiata) and Gray langur (Semnopithecus entellus thersites) at Kalakkad and Mundanthurai Tiger Reserve, India. Photo from TrekNature by Gopi.

Interspecies grooming is not unheard of and does occur naturally. While grooming can be dyadic and triadic (or even more), it can also be one-directional. Since grooming is central to primate sociality, there are reported instances of grooming between two different species of primates or even between a primate and non-primate. Grooming has many functions: hygiene, social bonding and even gaining favor.


I found this video yesterday (above) on Youtube by thekingchivas. I could not believe my eyes with what the camera caught. It shows a Malayan tapir (Tapirus indicus) being groomed by a White-cheeked gibbon (Nomascus leucogenys). After doing a Google search, I realize that this is not an isolated incident. Apparently The Bronx Zoo is also aware of this behavior and had posted its own video, which seems to be a separate incident from the one caught by thekingchivas.


I'm not going to definitively say that the tapir will not reciprocate in this grooming but chances are highly unlikely. I wonder what makes these gibbons (there were two females in the exhibit, The Bronx Zoo currently has a mated pair) groom their fellow exhibit-mate. While this might not be an altruistic exchange, we can view it as a mutual symbiotic relationship. Neither animal had its fitness reduced, so it is not altruism. Instead, both individuals benefit from this interaction so it is symbiotic.

The gibbons meticulously groom the tapir to remove insects, which in turns become a tasty snack for these gibbons. The tapir on the other hand, benefits by having pesky insects removed off its body. Is it significant that both animals are female? Is this behavior natural? There are recorded accounts of interspecies grooming between primates and non-primates, so it is quite likely.

A macaque grooming a goat on the streets of Chilkur, India. An example of mutual symbiosis between a primate and a non-primate. Photo by Libran Lover from A Lover's Journal.

A langur grooming a pig in Jaipur, India. Somehow nature managed to put two animals that I have polar opposite feelings together (one I love, the other I hate). Another example of mutual symbiosis between a primate and a non-primate. Photo by Christa Kate Hyland from Laddus and Langis.

The range of both Malayan tapirs and White-cheeked gibbons does not overlap. Malayan tapirs occur in Malaysia, Indonesia, Thailand and Myanmar while White-cheeked gibbons are found in Vietnam, Laos and the Yunnan province of China. Therefore, interspecies grooming between Malayan tapir and White-cheeked gibbon is probably a novel behavior that cannot be observed in the wild.

Map shows the current and historic range of Malayan tapir, as of 2003. Notice that Malayan tapirs do not occur in Vietnam, Laos nor China (Yunnan province) where White-cheek gibbons occur. Illustration by Sasha Kopf from Wikipedia.

Wordless Wednesday

Photo of the day: Polymorphism in Ebony langurs

Silver leaf langurs (Trachypithecus cristatus cristatus) Ebony langurs (Trachypithecus auratus auratus) are endemic to the islands of Java but the red morph (like the one above) occurs only in the eastern part. Photo taken at Bronx Zoo's Jungle World.


Correction: Thanks to reader Vincent Nijman for pointing out that it is an Ebony langur, not Silver leaf langur. That oughta teach me to write notes, not use mental notes.

Baby Sumatran Orangutan Born in Philadelphia Zoo

While Ardipithecus ramidus was all abuzz in the paleontology, physical anthropology, primatology and science blogosphere yesterday, the folks at Philadelphia Zoo were keeping themselves busy for another addition to their PECO Primate Reserve.

 Sugi, the proud father. Flickr photo from Kevin Burkett.

A baby was born to the zoo's resident Sumatran orangutan family (Pongo abelii), Tua (16 years old) and Sugi (13 years old), on Oct 2nd at around 8am. This is the first orangutan baby born at PECO Primate Reserve since it was opened in 1999 and also the first offspring for both Tua and Sugi. No words yet whether the baby is a boy or a girl.

According to Philadelphia Zoo's press release, both mother and baby appear to be doing well. The first 48 hours are crucial for the baby so zoo staff and veterinarians are closely monitoring both Tua and her baby. They do not know when Tua and her baby will make their debut at the PECO Primate Reserve.

Congratulations Tua and Sugi! See you soon.

A Cross-Species Comparative Study: Grooming Patterns in Captive Populations of Hamadryas Baboons and Geladas

This is the thesis that I've been working on for the past year. Finally got it graded and I am really happy about the thesis. After writing this thesis, I have more follow-up questions pertaining to grooming than I had started with so I guess it's a good thing.

Thanks to Dr. Larissa Swedell for supervising my thesis. Also, thanks to Dr. Sara Stinson and Dr. Ekaterina Pechenkina for reading the thesis and your inputs.

Abstract:
Primates groom themselves (autogrooming) and each other (allogrooming) for a variety of purposes. Allogrooming is arguably an altruistic behavior, and may be explained by kin selection. The purpose of this study is to better understand the grooming patterns of captive hamadryas baboons (Papio hamadryas hamadryas) and geladas (Theropithecus gelada) within the context of kin selection theory, which posits that kin will interact, especially in altruistic ways, more than non-kin.

This study hypothesizes that grooming patterns in hamadryas baboons and geladas can be explained by the patterns of philopatry, dispersal, social system and bonding that are seen in wild populations. The results of this study show that there is a higher frequency of allogrooming than autogrooming in both hamadryas baboons and geladas. It also shows that gelada leader males groomed their females more than hamadryas leader males groomed their females, which does not support the hypothesis of this study. The following results showed a trend but were not statistically significant enough to support the hypotheses: female hamadryas baboons and geladas groomed more than male hamadryas baboons and geladas; hamadryas leader males groomed their females more than females groomed among themselves in the same hamadryas group; gelada females groomed each other more than gelada leader males and their females; male hamadryas baboons groomed more than male geladas; female geladas groomed more than female hamadryas baboons; hamadryas baboons groomed more than geladas.

In addition, this study also hypothesizes that there is a correlation between grooming frequency and temperature. There is a positive correlation between grooming frequency and temperature in hamadryas baboons but a negative correlation in geladas.

A Cross-Species Comparative Study: Grooming Patterns in Captive Populations of Hamadryas Baboons and Geladas

Geladas and Hamadryas: A Comparative Study Of Grooming

I'm currently working on a Senior Honors Thesis before I graduate this Spring. It's a comparative study of grooming between gelada baboons (Theropithecus gelada) and hamadryas baboons (Papio hamadryas hamadryas). This study is being done in The Prospect Park Zoo and The Bronx Zoo (Both are Wildlife Conservation Society Parks). Prospect Park Zoo houses a troop of hamadryas baboons indoors while gelada baboons can be found in an outdoor exhibit at The Bronx Zoo.

I will write about how my research is progressing on this blog, along with news and articles related to primates and hominins.

Below are some pictures of my focal animals.