Dian Fossey Gorilla Fund Blog

Dian Fossey Gorilla Fund Blog RSS Feed
Do mountain gorillas avoid inbreeding?
Thursday, May 21, 2015

The long-term studies of mountain gorillas conducted at the Dian Fossey Gorilla Fund’s Karisoke Research Center continue to yield important information about many aspects of gorilla life. A study just published in the journal Behavioral Ecology and Sociobiology, focusing on gorillas monitored by the Fossey Fund, used genetic analysis based on fecal samples that have been collected since 1999. They were analyzed to determine paternity patterns and to look at whether gorillas avoid breeding with close relatives.

The study was co-authored by Fossey Fund CEO and Chief Scientific Officer Tara Stoinski, Ph.D., in collaboration with our long-term scientific collaborators at the Max Planck Institute for Anthropology.

Silverback Cantsbee has sired more than 20 offspring.The new study built on an earlier one, which examined paternity patterns through the late 1990s and found that in groups containing two or three fully adult males, the dominant silverback still sired the majority (85 percent) of offspring.

The current study included another decade of paternity data, which represented a time when the Karisoke gorilla groups grew very large and contained many more males ─ sometimes up to eight silverbacks. Under these conditions, the dominant males sired fewer offspring, although they still maintained the lion’s share of reproduction. Perhaps the costs of losing reproductive opportunities might be offset by the benefits of having male successors, who can keep the group together upon the dominant male’s death.   

Another focus of the current study was to look at inbreeding avoidance. Roughly half of females reproduce in the group where they were born, resulting in the potential for them to reproduce with their fathers. However, the genetic analyses in this study found no evidence of father-daughter reproduction, although half siblings were observed to occasionally reproduce. 

How fathers and daughters avoid breeding with each other is unknown — the authors suggest that females may use male age as a cue, since the daughters of dominant males all bred with males who were much younger than their fathers. 

As the authors state, these results emphasize “the complexity of social dynamics in one of our closest living relatives.”

Silverback Ugutsinda ailing, not seen regularly
Wednesday, May 20, 2015

Fossey Fund field staff are very concerned about the well being of 24-year-old dominant silverback Ugutsinda, who is the leader of the Ntambara group of mountain gorillas, one of the larger groups we monitor regularly. He suffered from severe illness in February and was left behind by his group in early March. However, he gradually recovered and rejoined his group on March 17, at which point we hoped a full recovery was underway.

Ugutsinda in MarchBut, on May 11, he was missing from his group again, then seen far from the group on May 16, at which point he was visibly ill and moving slowly, in addition to having lost weight. On May 17 he was seen again alone, vocalizing as though to find his group. Since then he has not been seen (as of May 20).

Ugutsinda’s health and whereabouts have required extreme efforts on the part of our field teams, with two to three extra teams often searching for him, sometimes with the additional of personnel from the Rwanda park authorities (RDB).

With the recent deaths of other dominant and leading silverbacks, the status of Ugutsinda has taken on very high importance. In fact, his group is named after former leader Ntambara, who disappeared in February and is presumed to have died.

Stay tuned for updates on this blog, since the situation may change quickly.

Illegal trade in natural resources affects Congo wildlife
Wednesday, May 13, 2015

A new report from the United Nations Environment Programme (UNEP) and partners states that organized crime and illegal trade in natural resources continue to create conflict in eastern Democratic Republic of Congo (DRC). According to the report, gold, minerals, timber, charcoal and wildlife products, with an estimated value of around $1 billion, are exploited and smuggled illegally, with some of the trade and most of the net profits going to transnational organized criminal networks based outside DRC.

The conflict in DRC has led to the loss of more than five million people over some two decades, and has also threatened the area’s important wildlife, including two types of gorillas (mountain gorillas and Grauer’s gorillas). Illegal mining and charcoal trading, and the resulting increase in deforestation, as well as bushmeat trade (which feeds both mining and charcoal camps as well as local populations and those in cities far away) are some of the issues that affect the gorillas and their habitat.

Congo landscapeThe Dian Fossey Gorilla Fund works in eastern Congo to study and monitor endangered Grauer’s gorillas, from two field sites – one in Kahuzi-Biega National Park and one in the remote Nkuba-Biruwe area. To work in Nkuba-Biruwe, our staff must deal with armed groups and continued insecurity. This is an everyday challenge but our work has continued successfully so far. However, a lack of law enforcement means there is no direct way to deal with poaching. Our focus has been to try and sensitize local communities, to show them that harming the forest is actually harmful to the whole community, and to get them to reduce hunting in areas where great apes need to be protected.

“In the past two decades, the local community living near Nkuba-Biruwe has seen wildlife disappearing from the forest. Elephants and red colobus monkeys are now locally extinct as a result of ivory and bushmeat trade, and gorillas and buffaloes are next on the list. We work closely with the community to implement solutions that benefit both humans and wildlife,” explains Dr. Damien Caillaud, the Fossey Fund’s Grauer's Gorilla Conservation and Research Program director.

In a UNEP press release, Achim Steiner, UN Under-Secretary-General and Executive Director of UNEP, said: "There is no room for doubt: wildlife and forest crime is serious and calls for an equally serious response. In addition to the breach of the international rule of law and the impact on peace and security, environmental crime robs countries of revenues that could have been spent on sustainable development and the eradication of poverty."

To read the full report, click here:


New study sheds light on mountain gorilla personalities
Monday, May 04, 2015

Like people, animals show a wide variety of personalities, and when it comes to great apes and other non-human primates, knowing more about them is particularly interesting. In addition to understanding why certain personality types have evolved, such knowledge could also inform how personality affects critical aspects of an animal’s life, such as mortality patterns, reproductive success, and mate choice.

Two young mountain gorillas with personality!But how can gorilla personalities be studied?  With people, scientists can use various tests (think of the famous Rorschach ink blot test), run experiments, or ask subjects to fill out questionnaires. For gorillas it’s a bit of a different challenge, yet in a study recently published by a number of Fossey Fund scientists, gorilla personalities were actually rated by using detailed questionnaires very similar to those used in human studies!

These were special, detailed, standardized questionnaires developed specifically to study non-human primate personalities, and the raters were experienced gorilla observers with training in collecting data on gorilla behavior. Led by Fossey Fund scientist Dr. Winnie Eckardt, the study (which was published in the Journal of Comparative Psychology) included eight raters, ran for seven months, and resulted in 556 ratings of 116 mountain gorillas that are routinely monitored by the Fossey Fund.

The main goal of the study was to describe the personality structure of these mountain gorillas based on particular dimensions, which the scientists called: dominance, openness, sociability, and proto-agreeableness. A gorilla high on dominance is a socially high-ranking individual, intelligent, decisive but also protective, helpful and sensitive – the wise leaders and protectors. Gorillas who rate high on the open dimension love to explore, are creative, impulsive, active, emotionally less stable and lack caution – the adventurer and daredevil types. Sociable gorillas are characterized by a high desire to interact with other gorillas, and show high levels of sympathy, affection and gentleness. Those who scored high on proto-agreeableness (similar to human agreeableness) are friendly, emotional stable and content – the “oases” of calm and peace.


However, when scientists try to assess animal personality, it is important to avoid projecting our own feelings and interpretations of the animals’ behaviors. One way to test this reliability is to associate the personality dimensions with certain observed behaviors. Our scientists did this using the long-term behavioral data collected by the Fossey Fund over past decades. For example, we found that gorillas ranked high in sociability groom other group members more often than gorillas assessed low in sociability. 


Gorilla aloneSince standardized methods were used, the results of this study could also be compared to those from studies on other apes, such as chimpanzees and orangutans. The findings suggest that differences in personality among apes, including humans, may reflect adaptations to their society and environment in order to optimize success and survival. For example, openness has been identified as a personality trait in humans, chimpanzees and gorillas, but not in orangutans. Orangutans are the only apes living solitary lives, as opposed to life in social groups. Openness may therefore be an important personality aspect for group-living primates with complex social structures but less important for the success and survival of a solitary-living primate such as the orangutan.

Other authors of the study included Fossey Fund President/CEO and Chief Scientific Officer Dr. Tara Stoinski, former Fossey Fund scientists Dr. H. Dieter Steklis and Netzin G. Steklis, Dr. Alison Fletcher and Dr. Alexander Weiss.


Rescued gorillas in Congo get new forest enclosure
Wednesday, April 29, 2015

The Gorilla Rehabilitation and Conservation Education (GRACE) Center in eastern Democratic Republic of Congo reached a major milestone this week by officially opening a 24-acre forest enclosure for its 13 resident Grauer’s gorillas, all orphans that were rescued after being illegally captured by poachers and traders. GRACE is the only facility in the world that provides rehabilitative care for this highly endangered gorilla subspecies, and ultimately aims to reintroduce gorillas back into the wild.

GRACE was founded in 2009 by the Dian Fossey Gorilla Fund International in collaboration with the Congolese Wildlife Authority (ICCN) and the Tayna Center for Conservation Biology. It has operated as an independent nonprofit organization since August 2014. The forest enclosure project, which has been called the gorillas’ “Freedom Fence,” was made possible by a major fundraising campaign by the Fossey Fund, along with contributions from GRACE partners the Dallas and Houston Zoos, and by a grant from the Margot Marsh Biodiversity Foundation.

GRACE forest enclosure aerial viewIn 2012, GRACE began building a 10-hectare (24-acre) enclosure for the gorillas inside former gorilla habitat adjacent to the Tayna Nature Reserve in the Kasugho region of North Kivu Province. They were first introduced into their new habitat in March 2015. The forest enclosure consists of mature trees as well as dense undergrowth and therefore provides an ideal environment for the gorillas to practice survival-critical skills such as foraging, nest building, and coordinating group movements. The enclosure is the largest of its kind in the world.

GRACE’s remote, mountainous location made construction a major challenge. Without access roads available at the construction site, every piece of equipment and material used had to be carried up and down the mountain. The project enlisted the help of over 200 people from local communities, more than half of them women. Gorilla experts from the Dallas and Houston Zoos and Disney’s Animal Kingdom also consulted on the enclosure’s design and construction.

 “The Fossey Fund is thrilled to see the Freedom Fence completed and the GRACE gorillas one step closer to living like they would in the wild,” said Dr. Tara Stoinski, CEO/Chief Scientific Officer of the Fossey Fund and a GRACE Board member. “Our staff cared for many of these gorillas for years and so it is especially meaningful for them to see them enjoying their new home. We are very grateful to all the Fossey Fund donors who helped make the fence a reality and congratulate the GRACE team and its partners on all the incredibly hard work that went into building the fence.”

GRACE gorillas eating in forestThe GRACE gorillas are between 3 and 13 years old and live in a single group, which serves as their surrogate family. For some of them, the opening of the forest enclosure was their first forest experience since being captured from the wild. However, upon entering their new space, the gorillas acted immediately at ease and began feeding on vegetation and climbing trees. The group now spends more than 6 hours each day inside this new habitat, and they are adjusting wonderfully to forest life.

“When the gorillas took their first steps into their new forest habitat, it was an incredible moment for GRACE,” said GRACE Congo Director, Luitzen Santman. “The staff and community have worked so hard over the past three years to achieve this milestone for the gorillas. We watched proudly and with great excitement as the gorillas took to the forest like they had never left it.”

A research team at GRACE now observes the gorillas throughout the day from five towers situated around the enclosure’s perimeter. The goal is to track how the group uses the forest and how it is impacting the gorillas’ rehabilitation progress.

GRACE also works with local communities on conservation education to help protect the Grauer’s gorillas remaining in the wild, particularly in the Tayna region.  The new forest enclosure will play an important role in these efforts as well. Local schoolchildren and adults will soon be able to visit GRACE to view gorillas from a platform outside the enclosure. This educational program will teach about Grauer’s gorillas and the threats they face while instilling pride in visitors for having this great ape as part of eastern DRC’s natural heritage.

GRACE gorilla and viewThe forest enclosure marks the next chapter in the rehabilitation process for the GRACE gorillas. Whether reintroduction will be possible awaits further study, but in the meantime, this new habitat provides the ultimate playground for the young gorillas.

“The gorillas have been through so much,” said GRACE Executive Director, Dr. Sonya Kahlenberg. “They lost their families, survived capture, and were rescued from terrible conditions. Providing this enclosure so they can reconnect with their forest home is the very least we can do.” She added, “When you see them up in the trees foraging and playing together, it’s just incredible. Their resiliency never ceases to amaze me.”

For more information about GRACE, please visit http://gracegorillas.org/. To view a video slideshow of the forest enclosure, click here

Adopt a Gorilla for Dad

Give your Dad a meaningful gift this Father's Day.

© 2012 Dian Fossey Gorilla Fund International, Inc. All Rights Reserved.

Follow Us @