There are four species of great apes: chimpanzees, gorillas, orangutans, and bonobos. You might be tempted to call them monkeys, but apes are actually different from monkeys. The difference between a monkey and an ape is that a monkey has a tail and an ape does not. Apes are also considered to be more intelligent than monkeys. There is another word you can use to refer to both apes and monkeys: primates. That’s where our exhibit, the World of Primates (or the WOP, as we sometimes like to call it for short), got its name. We have both monkeys and apes in this exhibit.

Great apes are some of the smartest species in the animal world. They have been documented using their brains in a number of impressive ways. In the 1960s Jane Goodall was the first person to witness a great ape use a tool in the wild. She watched as a wild chimpanzee used a stick to find ants underground. Since then, other observations in the wild and in Zoos have continued to highlight these animals’ intelligence. Some great apes have been taught to speak with sign language, while others have defeated humans in memory games. Most recently, great apes have even been playing with iPads.

Most of the great ape species live in central Africa, except for the orangutan, which lives on the Asian islands of Borneo and Sumatra in the South Pacific. With such a limited range, these species have become vulnerable to population declines. Unfortunately, chimpanzees, gorillas, orangutans, and bonobos are all listed as endangered.

There are two species of gorillas (eastern and western) and four or five subspecies. We have five Western lowland gorillas living here at the Fort Worth Zoo. Gorillas are herbivores. Most of their meals consist of fruit, leaves, and plant stems. Gorillas are the largest of all primate species. Males are often as much as twice the size of females, with average weights in the wild ranging from 350 to 400 pounds.

Of all the primate species, gorillas are the largest. Wild males may weigh up to an average of 350 to 400 pounds.

Heart disease is the most known cause of death in humans (even more common than cancer). It is also the most common cause of death in gorillas, especially males. This disease occurs when blood vessels become narrow or blocked, making it difficult for blood to flow through the body. There are other forms of heart disease such as infections and conditions that affect the heart’s beating rhythm.

We don’t know what is causing heart disease in gorillas, but in an effort to find the reasons, the Fort Worth Zoo has joined 34 other Association of Zoos and Aquariums (AZA) Zoos in a research project called the Great Ape Heart Project. Started in 2010, the Great Ape Heart Project is the world’s first-ever organized effort to combat heart disease in the four endangered great ape species. The project aims to answer three questions: Why does heart disease affect the great apes? How can we improve the treatment of affected apes? How can we help captive apes live healthier lives? All the organizations participating in the Great Ape Heart Project will compile the data they collect from their research to form a huge database of information. Hopefully, with all this information, biologists will be able to start piecing together some answers.

The goal of the project is to train gorillas to allow biologists to perform heart monitor tests while the apes are awake. In the past, these tests have been done while the gorilla is asleep or under anesthesia. Doing tests under these conditions is less effective for a number of reasons. Anesthesia can put stress on the animal’s body. Having to wait until the animal is asleep or under anesthesia means that tests cannot be done very often. Anesthesia also may affect the gorilla’s heart so it looks or acts differently while being studied, giving biologists incomplete or incorrect information.

In the spring of 2011, the Fort Worth Zoo began training two of its gorillas, Ramses and Amani, to have heart monitor tests done while they are awake. Each gorilla learned to press its chest against a barrier made of wire. The barrier separates the zookeeper from the animal, but it allows keepers to perform a heart ultrasound on the gorilla. As a reward for cooperating, the gorilla receives a treat.

In September 2011, Ramses allowed Zoo staff to successfully perform the first heart ultrasound while he was awake and participating. What a great accomplishment! This speaks to what a great staff we have here at the Fort Worth Zoo and what intelligent creatures gorillas are.

So far the organizations participating in the Great Ape Heart Project have been able to establish normal ranges for a healthy gorilla heart. Next up is finding normal ranges for the three other great ape species: chimpanzees, bonobos, and orangutans.

While we’re working to save great apes in the United States, don’t forget that these creatures are really in trouble in their native habitat. Illegal hunting for meat and the pet trade, habitat alteration, and disease have put the great apes in danger of extinction.

Great apes are in trouble, and they need our help! What can you do?

  • Visit the World of Primates at the Fort Worth Zoo to catch a glimpse of the endangered great ape species. The Fort Worth Zoo is actually the only Zoo that houses all four species! You can also see other interesting African primate species, such as the brightly colored mandrill and colobus monkey.
  • Recycle used cell phones. Cell phones contain a substance called coltan, which is mined in gorilla habitats. Recycling used phones means reducing the need for new phones, reducing the need for mining in gorilla habitats, and reducing the amount of landfill waste.
  • Shop responsibly and buy products that use sustainably harvested palm oil. Palm oil (found in everyday foods and healthcare products) is harvested in areas where orangutans live. The resulting habitat alteration is putting orangutans in danger of extinction. Use this shopping guide on your next trip to the grocery store.
  • Use recycled paper products and encourage others to do the same. Deforestation is one of the main causes driving great apes out of their habitats. Recycling and reusing paper reduces the need for new trees (trees that are possibly in great ape habitat) to be cut down and manufactured into paper.

We’ve learned so much on our adventures so far, and I can’t wait to show you what’s next. As always, if you have a conservation story or idea don’t forget to drop me a note in Sam’s Inbox ( Thanks for all you do! Happy Exploring!



Affect: (verb) to act on or cause a change
Aim: (verb) to point or direct toward something
Anesthesia: (noun) medicine usually given to an organism so it is asleep or unconscious during surgery or medical procedures
Barrier: (noun) something that blocks passage, such as a wall, fence, etc.
Blood vessel: (noun) a small passage (such as an artery or vein) that blood travels through from the heart to the rest of the body
Captive: (adjective) kept in a protected area under human care
Classify: (verb) to separate or organize into related groups
Cooperate: (verb) to work or act together willingly and agreeably toward a common purpose or goal
Compile: (verb) to put together from several sources into one
Combat: (verb) to fight against
Consist (of): (verb) composed or formed of
Database: (noun) a collection of related data that is located in one place (usually a computer)
Deforestation: (noun) the act of clearing forests or trees from an area
Document: (verb) to record or write down details for later reference
Effective: (adjective) successful in accomplishing a goal or task
Endangered: (adjective) at risk for extinction
Establish: (verb) to bring into being
Extinction: (noun) a coming to an end or dying out
Great ape: (noun) Apes of the family Hominidae, characterized by high intelligence and the absence of a tail. Includes humans, gorillas, chimpanzees, orangutans, and bonobos.
Habitat: (noun) the natural environment of an organism
Habitat alteration: (noun) change that takes place in a habitat caused by natural or human processes
Harvest: (verb) to gather
Herbivore: (noun) an animal that feeds primarily on grass and other plants
Highlight: (verb) to spotlight, illuminate, or draw attention to
Impressive: (adjective) striking or remarkable
Improve: (verb) to make better
Infection: (noun) a medical condition when germs contaminate or poison body tissues
Limited: (adjective) restricted, confined, not far-reaching
Narrow: (adjective) skinny, the opposite of wide
Native: (adjective) being from the place or environment in which a person was born or a thing came into being
Observation: (noun) the act of noticing something by watching it with your own eyes
Primate: (noun) a group of mammals consisting of apes and monkeys
Stress: (noun) pressure or force placed on one thing by another, strain.
Species: (noun) a group of individuals having some common characteristics or qualities
Subspecies: (noun) a species within a species
Ultrasound: (noun) a medical procedure that produces a picture of the inside of a body
Vulnerable: (adjective) easily targeted, likely to be attacked, unprotected, exposed
Witness: (verb) to see, hear or perceive something in person

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