Tuesday, January 24, 2017

#ElephantTuesdays: oh mama! a female´s role 🐘

It is generally known that elephants live in -large- groups, and even that these groups are leaded by a female. But how are they formed? How is the decision made? What are the duties of a leader in the group? There have been several studies on this interesting topic; a very relevant one is known to be the longest continuous elephant research project ever developed, was conducted at Amboseli National Park in Kenya

Elephants live in a fission-fusion society, accumulating social and ecological knowledge over decades, and with mother-offspring bond units to clans. These groups gather approximately 8-12 individuals (in the case of African Forest Elephants the groups might be smaller), are formed by related females and leaded by the matriarch, who is typically the eldest and largest female. All members feed, rest, move and interact in a coordinated way and have very close ties.

Family groups are active, as they constantly build up and break down, and therefore it´s usually difficult to distinguish a completely formed group, but generally speaking, four different kinds of units can be distinguished among elephant fission-fusion social structures:

Mother-calf units: both in Asian and African elephant societies, calves lie at the core of the elephant family with the matriarch serving as the head.

Familywithin the family group, young females (nulliparous) are engaged as the so-called allomothers

 original video: ACP0002hmo

Bond groups: herds can split in related groups, that might at some point gather in closely related families, also called kin groups. Bond group ties are weaker than family ties, but still bond group members assist and defend one another.
Clans, or assemblages of bond groups. Clans are defined as those families and bond groups that share the same dry season home range.

Mother-calf units and families are stable groups, while bond groups and clans are known to be seasonal.

As the eldest female of the group, a matriarchs is a `source of knowledge´ to the others, and in a female-led society, the individual role is the result of age, size, kinship and reproductive condition. The bonds to the matriarch are so strong, that the herd would possibly break after a matriarch´s death.

The matriarch´s tasks are:

·     To lead the group; she will decide when and where to wander, and as a result, what to feed on. She also knows where to go to find the best water sources. However, suggestions are often made by any other member of the group, typically by adults.
·      Protection; she keeps the group away from threats, like human settlements, etc. She will place herself in front of the potential danger, so that she will be attacked first. She will then be protected by the other females of the group, confirming their strong family bonds.
·      She controls the group, noticing where other members are to gather them in case or danger.
·      She educates the group: by teaching the next matriarch.

The female in the group who is a potential matriarch is hard to tell apart; some elephants are natural born leaders, and they start to display their leading abilities at an early age, but sometimes not. As a general rule, a female will succeed in her attempts to be the matriarch if she is confident, well-connected and able to command the respect of others. And all these qualities must be proven all over the years, until the members of the herd are able to recognize her as their leader. So the wise matriarch will be a combination of both natural leadership qualities (“personality”) and long experience; thus, she needs to be genetically and socially well connected to all the members of the group.  

And what about the males? What is the male role in an elephant society? In former elephant posts we discussed about the different life stages of the elephants. When adolescence occurs (at the age of 6 – 15), males leave the matriarchal herd to join other males. Independent males are seen in small male groups, and will go from one family to the next during sexually active periods. The males can build strong bonds, but still not so strong like families.
Young males often gather in unstable bachelor groups (all-male groups), sometimes associated with an adult male. Solo males have already reached the adult age:

original video: ACP000c165 

* In the video below, could you tell who the matriarch is?


Murray E. Fowler, Susan K. Mikota (2006): Biology, Medicine, and Surgery of Elephants

Elefanten in Zoo und Circus, European Elephant Group (EEG), Das Elefanten-Magazin, January 2015.

Elephant Voices: https://www.elephantvoices.org/

*answer here

Tuesday, January 17, 2017

#ElephantTuesdays: the elephant´s vision 🐘

The elephant´s eyes are quite small If one compares them with their body dimensions. Their sense of vision is moderate, as they lean more on their olfactory and auditory senses instead.

The eyes of an elephant are located on the sides of the head and therefore provide better peripheral vision, rather than binocular vision. 

Elephants (and especially African Forest elephants) have long eyelashes to protect them from the blowing sand, dirt, debris and the dense vegetation:

original video: ACP0002hmp

In addition to the upper and lower eyelids, and like many other animals, all elephants species have a third eyelid (the so-called nictitating membrane, from latin nictare, to blink) which moves horizontally across the eye, and which works for moisten and protection when bathing or dusting.

Some elephants develop a white ring that encircles the iris as they mature. This ring is similar to an age-ring that may develop in humans (as they age) called arcus lipoides, and does not affect vision.

Elephants are dichromatic; they have two kinds of color-sensors in their retina, one type of cones for *reds and another for greens. That means that they are "color-blind" when you compare them to humans (we are trichromatic: we have three kinds of cones: red, green and blue).

What is also interesting is that they are one of the animals that exhibit arrhythmic vision, that is, their vision changes within the daytime. At night, their eyes are most sensitive to violet light so they can see pretty well under the smallest amount of daylight when the prevailing color of the atmosphere is in the violet range. They have pretty sensitive rods as well (the higher density of rods in the retina, the more sensitive to light one can be), so elephants do a good job when it comes to night vision compared to humans.

The eyesight of the elephants is thought to reach a range of about 46 m. However, this can vary and be much shorter, probably because elephants use their vision sense less than their olfactory and auditory senses. When they focus on their vision, however, they show to react to the smallest ear movement of another elephant placed up to 50 m. in the distance. 

The elephant eyes are amazingly beautiful, and like humans, they can show different colors; the four most common eye colors are dark brown, light brown, honey and gray, but there are more tones like: blue-gray, gold, brown tones, green and yellow, and even the right and left eye of one elephant can be differently colored.

As a curiosity: There have been documented occurrences of elephant herds being led by a blind member, fulfilling amazingly its role as the herd leader.

*Some authors claim that elephants possess cones for reds and blues (deuteranopia) instead of reds and greens : Von Elefanten und Menschen, Fred Kurt (2014).


Murray E. Fowler, Susan K. Mikota (2006): Biology, Medicine, and Surgery of Elephants

Fred Kurt (2014): Von Elefanten und Menschen.

Seaworld Parks & Entertainment: https://seaworld.org/en/Animal-Info/Animal-InfoBooks/Elephants/Senses

Saturday, January 14, 2017

Leopards in the forest - new Chimp&See mini-project on predators

In December, we started another mini-project on Chimp&See preparing to assess predator density at the research sites. What sounds a little dry and analytical is actually quite exciting: with the help of our volunteers, we will identify individual leopards to get a clear picture of how many of them live in an area. These big and beautiful cats are known to prey on smaller primates and ungulates, but do not necessarily stop for bigger species, like chimpanzees.

Leopards in the forest – a short introduction 
We have already seen leopards on our camera traps at several sites in West and Central Africa. Leopards are the largest forest predators; at the savannah site Dry Lake we’ve seen leopards and lions alike. Much knowledge about leopards comes from the better known open habitats in East and South Africa, whereas forest leopards need to be studied better in their unique environment. Here, leopards do not have any other competition by big cats (no lions or cheetahs in the forest). The only other major predators are eagles - that are more relevant to more arboreal species - and the chimpanzees themselves.

Forest leopards live in the dense and moist rainforest with limited visibility of potential prey. As rainforests do not have a markedly seasonal rhythm like savannahs, there are also no significant prey migrations, offering a constant, but smaller supply of potential food for these carnivores. As a consequence, their home ranges are thought to be bigger than in open savannahs and woodlands, and the density (the number of individuals per square kilometer) to be higher. Although leopards are territorial and solitary, we expect a considerably overlap of their territories.

Leopards are opportunistic hunters. In addition to ungulates and smaller mammals, leopards hunt monkeys, but also chimpanzees and bonobos. Usually, they hunt prey smaller or equal in body size than themselves, but are known to successfully attack prey animals much bigger, like the large-bodied Jentink’s duikers. They prefer more terrestrial primate species that live in big groups, like sooty mangabeys. Forest leopards hunt mainly during the day and on the ground with an activity peak at dawn and dusk. This daytime hunting follows the diurnal activity pattern of their main prey species. Savannah leopards on the other hand, and also leopards in closer proximity to human settlements, prefer hunting at night – also because other competitors (e.g., lions) might prefer daylight hunting or steal the prey.

Leopard matching at Chimp&See 

To assess the predation risk of chimpanzees and other primates, we therefore need to know how many leopards live at one site. The mini-project will attempt this goal in two steps: first, we will tag all leopard videos with the respective age classes and, if possible, sex of the individuals as well all visible body sides to prepare for a direct comparison of the fur pattern. In a second – but eventually parallel – step, we compare this pattern and other traits of the leopards to assign individual IDs. The leopard fur pattern of dark spots and rosettes is highly individual and allow confident identification of an individual – at least if we get the same body side on camera twice. A detailed tutorial helps the volunteers to discuss their findings and present their arguments on the discussion board.

A detailed tutorial explains how to compare the fur patterns of leopards and present findings
Once a leopard is identified as the same individual in two separate video sequences, the volunteers can name it. Everybody can try it. Like all cats, leopards are extremely beautiful, elegant, and powerful animals. Even if you do not find a match, a close look on our footage is worth all your time.

  • Jenny D. Spatial organization of leopards Panthera pardus in TaΓ― National Park, Ivory Coast: is rainforest habitat a ‘tropical haven’? Journal of Zoology, November 1996. DOI: 10.1111/j.1469-7998.1996.tb05296.x 
  • ZuberbΓΌhler K, Jenny D. Leopard predation and primate evolution. J Hum Evol. 2002 Dec;43(6):873-86. 
  • Boesch C. The effects of leopard predation on grouping patterns in forest chimpanzees. Behaviour 117 (3-4) 1991
  • Bailey T. N. 1993. The African Leopard: Ecology and Behavior of a Solitary Felid. Columbia University Press, New York, 429 pp.

Monday, January 9, 2017

The Best of Chimp & See 2016

Thank you to everyone for a fun and successful Best of 2016 event! There were some really entertaining clips this past year, and I hope you enjoyed the chance to revisit them. Now, which ones did you think were the best? Here are the results from the voting!

Favorite chimp:

Winner: πŸ† Kamala πŸ† | Runners Up: Vili and DBInf04

Funniest clip:

Winner: πŸ† Off to school πŸ† | Runners Up: Jonah needs a hug and Still learning the jungle gym

Best camera reaction:

Winner:  πŸ† Maryln tries to figure things out πŸ† | Runners Up (tie): Here, get my best side and Mom and baby get a close look

Creepiest clip:

Winner:  πŸ† Galagos shrieking in the night πŸ† | Runners Up: The floating head and Ant swarm

Cutest clip:

Winner: πŸ† Off to school πŸ† | Runners Up: Etta and baby playtime and Jonah needs a hug

Biggest surprise:

Winner: πŸ† Jackal's daytime close-up πŸ† | Runners Up: Filou, a male with a maternal instinct and Bespeckled chimp selfie

There we go -- the Best of Chimp & See 2016! Thank you again to those that nominated and voted during the event. Also, a very big thank you to all the volunteers who, one clip at a time, have brought us this far and will carry us on through an undoubtedly exciting 2017!

See you back at Chimp & See!

Sunday, January 1, 2017

VOTE NOW for the Best of 2016!

A few weeks ago, we asked you to nominate the best videos on Chimp & See in 2016 in the categories of Favorite Chimp, Funniest Video, Best Camera Reaction, Creepiest Video, Cutest Video, and Biggest Surprise.  It was challenging, but fun, and now it's time to vote for your favorites!

We set up a survey so you can view all the clips and send us your votes.  Based on feedback from last year, we made some changes to make this year's survey a little shorter (it should take about 15 minutes).  It's a great chance to look back over the fascinating and entertaining clips from the last year and share your thoughts on the best of the best.

As you view each video, you have the opportunity to give it a score of 1 (low) to 5 (high). Voting ends on Sunday, January 8th, after which we'll tally the scores to find the winners for each category.

The survey is open to anyone (one entry per computer), so feel free to share this "highlight reel" with your family and friends so they can join in the fun and add their votes, as well!

If you have any problems or questions, please let us know. Enjoy, have fun, and may the best clips win!

(You are free to enter scores for as many or as few videos as you'd like, but only one voting form can be submitted per computer.  Votes are anonymous.  Be sure to submit your votes before January 8, 2017, at 11:00pm EST.)