Transfers 2 - Bibi and Ernie

Bibi and Ernie.  Theirs is a love story.  It began with their introduction in 1990. Bibi was 22 years old and had arrived at the Denver Zoo in 1971.  Ernie was 7 years old and had only been in Denver for 8 months.  Ernie had been raised by his mother Katherine in a family group in Oklahoma City, but was by himself in Denver quarantine.  Bibi had been separated from her social companions, Joe and Maguba, for treatment of an abdominal abscess.  They were both yearning for gorilla companionship.  

Ernie was housed in three adjoining holding cages across the keeper aisle from the main gorilla exhibit.  On January 4, 1990, Bibi was moved into one of these holding cages.  For reasons known only to her, Bibi began to stand on her head repeatedly and continued until she joined Ernie.  I think she was excited and happy.  She and Ernie both peeked at each other under the separating door, and they could touch fingers around the door.  They both tried to open the door between them. Four days later a small mesh howdy window was installed in this door, and Ernie began to camp out at the door, watching and vocalizing to Bibi.     

When they were introduced a month later on February 8, Ernie was eager to make contact, but Bibi nervously tried to avoid him.  After an hour and a half, Bibi discovered that the doors separating the three cages were not locked open.  She went into the end cage and pulled the door shut between her and Ernie.  Ernie promptly opened the door, and they repeated this throughout the day.  After a couple hours, Bibi was displacing Ernie and establishing her dominance.  By the third day they were best friends, playing frequently (photo at right) and grooming each other.  They would spend the next 18 years by each other's side.

After Joe and Maguba were transferred to other zoos, I collected 20 hours of data each on Bibi and Ernie.  Here are their activity budgets:   

Bibi:  feeding 49%, locomotion 4%, abnormal 1%, self grooming 3%, solitary play 4%, inactive 34%, social 3%, misc. 2%     

Ernie:  feeding 63%, locomotion 2%, abnormal .3%, solitary play 7%, inactive 18%, social 8%, drink 1%, misc. 1%

Bibi spent 30% of her day engaged in enrichment activities, and Ernie 52%.  Bibi spent 16% of her time eating browse (photo below), Ernie 13%.  Bibi manually extracted food from portable treat boards 13% of her day (photo below); Ernie extracted this food 20% of his day, using tools about 2/3 of the time (photo below).  Both gorillas spent time at the fishing boards:  Bibi .6% and Ernie 19%. Bibi used her tongue and fingers, and Ernie used tools at the fishing boards (photo below).  He spent about 32% of his day using tools to obtain food.

Bibi's abnormal behaviors consisted of regurgitation and reingestion (R&R) of food and coprophagy (eating feces).  Her self grooming mainly consisted of using her fingers to groom her abdominal abscess.  Ernie exhibited a small amount of hair plucking.  Although he sometimes tried, he still had not perfected his R&R. Ever since his arrival at Denver, Ernie had drunk water more frequently than the other gorillas.  Drinking and peeing seemed to be his hobby.      

Bibi displayed aggressively toward Ernie 3 times, always in the context of food. Ernie had a healthy respect for Bibi's food dominance.  He never challenged her over access to food, and he usually moved to another part of the exhibit to eat, often carrying armloads of food.

There were 110 scores for play between Bibi and Ernie!  These affiliative interactions included play chase, play bite, tickle, wrestle, holding hands, and embracing or just touching each other (photo at right).  It was common for one of them to initiate a play session by shaking hay, wagging their head, or play biting their own hand or arm.  Or Ernie might run, somersault, or roll around Bibi as she sat or lay down.  Ernie enjoyed piling hay on top of Bibi, who would often respond by beating her chest.

In 1994 the Denver Zoo was preparing for a major renovation of their primate area, including a new great ape building.  In October Bibi and Ernie were moved to the Cheyenne Mountain Zoo in Colorado Springs.  This was to be a temporary situation, and Bibi and Ernie were housed in a cage in an off-exhibit holding building. However, when the Denver Zoo's new Primate Panorama was complete, a new family group of gorillas was transferred in from Chicago.  Bibi and Ernie would spend 2-1/2 years in this "conservation barn."

On April 4, 1997, Bibi and Ernie were moved to the Cheyenne Mountain Zoo gorilla exhibit (photo at right - classic Bibi pose).  Their previous silverback had been transferred to another zoo, and the gorilla group was composed of four females.  Two adults, Roxie and Juju (photos below), had been social companions for many years.  The younger females were Kwisha (photo below), who had come from the Cincinnati Zoo, and Asha (photo below), who was Juju's daughter.  They were both about 5 years old.  Roxie was the only female who had been raised by her mother; the other three females were human reared. The keepers were also hand rearing Juju's four month old daughter Zuri (photos below).

When I first saw Bibi and Ernie on April 16, I was stunned.  Bibi looked the same, but their isolation in the barn had affected Ernie both physically and emotionally. He had reached full maturity and was totally silvered.  But he looked out of shape, with a flabby belly and untoned muscles, and his hair was dull looking.  Gone was the sweet goofy boy, and in his place was what appeared to be a moody and angry adult.  Ernie was enormous (photo below), and Bibi deferred to him.

Initially Bibi and Ernie were introduced to all four females, but after Ernie injured Kwisha, she and Asha were removed.  The first time I saw them, Bibi and Ernie were with Juju and Roxie.  Juju was very nervous of Ernie, who tended to stalk her. It wasn't long before he had injured her.  Roxie was smitten with Ernie immediately (photo below), soliciting him for mating.  Bibi and Roxie formed a playful friendship right away (photos below).  It was a great situation for Bibi, since she was Ernie's favorite, and she was a happy camper (photos below). Ernie, Bibi and Roxie were usually in proximity to each other, but Juju kept herself separate.  After a few days, Ernie inflicted a small wound on Roxie when she intervened between him and Juju. Soon after, Juju was removed and happily reunited with Asha and Kwisha.

After a month in the gorilla exhibit, Ernie's muscles were more toned and he was physically looking better (photo below).  Because of tension between Ernie and Roxie, Bibi found herself torn between them and who to hang out with.  Within a couple months she was spending most of her time with Roxie instead of Ernie.

In October a new grouping was tried - Ernie by himself (photos below), and all five females together to give them a chance to form strong bonds.  Bibi was initially less confident without Ernie, but soon was playing with both Roxie and Asha (photo below).

Because Asha seemed interested in Ernie, in December the decision was made to "creep" the door separating them.  The door was opened wide enough for Asha to pass through, but not Ernie.  That way, being with Ernie could be Asha's choice. Ernie didn't react when she first entered his enclosure.  However, later when a keeper was coaxing Asha out of Ernie's area, Ernie attacked Asha.  Perhaps he didn't want her to leave.  The adult females tried to help Asha, but the door opening was too narrow for them to fit through.  A water hose was used to separate Ernie and to force him outside, where he was locked out in the cold until after it was dark.  Asha was badly wounded and required a lengthy surgery to repair her leg muscles.

About seven months later, Ernie was reintroduced to Bibi and Roxie, which went well.  On the second day, Bibi and Roxie got into a scuffle, and Ernie broke it up by pinning down Roxie without biting her - very appropriate behavior.  Bibi and Ernie were happy to be together again, playing, cuddling and sleeping together.  But when Juju was added to the group, Ernie attacked and injured her again, so she rejoined Asha and Kwisha.  By this time, Kwisha was covering her ears (photo below) and Asha had begun sucking her big toe.

It was decided that Bibi and Ernie would be transferred to the Knoxville Zoo, in exchange for Scotty, one of the silverbacks there.  When I observed them prior to their departure, they were housed separately (photo at right).  Because time was limited, I revised my data collection protocol and observed in 15-minute sessions, recording a behavior every 30 seconds.  I collected 8 hours of data, 960 data points, on each gorilla.  Observations were divided between when they were outside and inside.  Following are their activity budgets, as well as differences from their Denver data from eight years earlier:

Bibi:  feeding 19% (-30%), locomotion 7% (+3%), R&R 7% (+6%), self grooming 6% (+3%), solitary play 1% (-3%), inactive 57% (+23%), social 0% (-3%), misc. 3%     

Ernie:  feeding 22% (-41%), locomotion 9% (+7%), R&R 5% (+5%), hair plucking 22% (+21.7%), self grooming 3% (+3%), solitary play 3% (-4%), inactive 33% (+15%), social 0% (-8%), misc. 3%

Ernie's hair plucking had become compulsive.  He had large plucked areas on his upper and lower legs, his arms and shoulders, his belly and his head (photo below).  Sometimes he didn't actually pull out hair, but just made a plucking motion or picked at the bare areas.  Bibi spent an increased amount of time grooming her abdominal abscess.

There were no observations of Bibi and Ernie playing with each other.  However, they were usually in close proximity, and both of them initiated this by moving closer to the other.  They grumbled and grunted at each other over food or burlap bags, but neither seemed to pay attention.  They reminded me of an old married couple.  Whenever Ernie had visual access to the other gorillas, he was interested to watch them.

It's important to keep in mind how much time had passed since Bibi and Ernie's Denver data, especially concerning potential behavior changes that could have been connected with Ernie's maturation.  However, these data speak for themselves - significant decreases in feeding, solitary play, and social interactions; significant increases in abnormal behaviors, self grooming, and inactive.  Bibi and Ernie were on hold, awaiting their transfer to Knoxville.

Bibi and Ernie were transferred to the Knoxville Zoo in late 1999.  At the time of my observations in 2002, they alternated between the indoor enclosures and the outside exhibit with another group composed of an adult male Kwashi and a young male Bantu (photo below).  Although unrelated, these two males got along very well.  Kwashi was a mellow silverback who stuck out his tongue at people he liked.

Kwashi and Bantu had arrived in November 2001.  Keepers told me that before their arrival, Ernie was very happy-go-lucky and playful with keepers and with Bibi.  Ernie and Kwashi were so negatively affected by each other that it had been necessary to eliminate visual access between the two.

I observed Bibi for 8.5 hours (1020 data points) and Ernie for 8.25 hours (990 data points). Observations were evenly divided between when they were indoors (photo below) and in the outside areas (photos below).  Their activity budgets and differences from Cheyenne Mountain Zoo are as follows:

Bibi:  feeding 39% (+20%), locomotion 10% (+3%), R&R 0% (-7%), coprophagy 2% (+2%), self grooming 6% (same), solitary play 1% (same), inactive 40% (-17%), social 1% (+1%), misc. 1%     

Ernie:  feeding 24% (+2%), locomotion 6% (-3%), R&R 1% (-4%), hair plucking 28% (+6%), self grooming 2% (-1%), solitary play 3% (same), human orientation 2% (+2%), inactive 27% (- 6%), social w/Bibi 2% (+2%), social w/Kwashi 2% (+2%),  misc. 3%

Increases in feeding and decreases in idle time, especially for Bibi, were positive changes, as were decreases in R&R.  Bibi was moving around more, and her weight had dropped from 270# to 235#.  Ernie weighed in at a whopping 420# and looked very fit (photo below).

Bibi's abdominal abscess had improved, and she was treated regularly by a team of veterinarians from University of Tennessee.  This meant regular "knock downs" (being anesthetized), but Bibi had evidently become accustomed to this.

When Bibi and Ernie were in the outside exhibit, there were lots of opportunities for them to eat browse.  Ernie had a technique where he pulled the small trees down to him (photo below), which allowed Bibi to eat the leaves too.

Even though Ernie's hair plucking scores increased, he actually looked much better (photo below).  His plucking scores in Knoxville also included picking at plucked areas.  Bibi's coprophagy usually included "fecal art," a favorite behavior of gorilla keepers everywhere - not! Prior to eating the feces (her own or Ernie's), Bibi spread it across a wall and picked through it for the tasty undigested bits. This was not a new behavior for her.

Ernie's indirect aggression toward Kwashi consisted of banging on the doors separating them and positioning himself so he could see Kwashi's reflection and then standing rigid.  Ernie's human orientation mainly occurred when he and Bibi were inside and he watched the keepers.

It was a pleasure to see Bibi and Ernie interacting again.  As always, they were usually in close proximity to each other (photo below).  Their social interactions included laying together, a small amount of play, playful displays, pleasure rumbles, and copulations.  They copulated repeatedly on two consecutive days, always face-to-face (ventro-ventral), with Bibi's little feet sticking up on either side of Ernie.  The more common mating position for gorillas (and mammals in general) is for the male to mount the female from behind (ventro-dorsal).  Bibi and Ernie's mating position seemed to reflect their affection for each other.

When I was observing Bibi and Ernie inside, I could hear their vocalizations, which was a pleasure I didn't usually have while observing gorillas through glass. Occasionally Bibi would threat bark or scream at Ernie over food, but he paid no attention and just kept eating.  Most of the time they alternated rumbling at each other, as if they were having a conversation, which I suspect they were.

Bibi died on Christmas day 2007.  Ernie was inconsolable in his grief.  Click below and scroll down to page 54 for Lee-Ann Hartlett's beautiful article about Bibi and Ernie's loving relationship, and Ernie's mourning and recovery.   

http://pin.primate.wisc.edu/news/journals/GorillaGazette/gaz2008/gazette-may08.pdf     

I'm so grateful Bibi and Ernie were allowed to stay together.  With Bibi's health problems, I don't know if she would have survived without Ernie, who always looked out for her. Ernie appeared to need her as much as she needed him.

photo from Knoxville News Sentinel 2007  

This photo captures her Bibi-ness.

All four gorillas were transferred from the Denver Zoo.  With the exception of locomotion, which is understandable in captivity, the average activity budget of the four in their last Denver observations compared favorably with that of western lowland gorillas in the wild:     

Denver:  feeding 47%, idle 37%, locomotion 3.5%  

Africa:     feeding 55%, idle 35%, locomotion 14%     

photo: Joe and Maguba, Denver Zoo 1990

Joe, Maguba, and Bibi were adults who were born and wild-caught in Africa.  They were then raised by humans.  Ernie was a juvenile who grew into adulthood.  He was born in captivity and raised by his mother in a family group.  Each gorilla had her/his own unique personality, quirks, and life experiences.

Joe (Brownsville gorilla exhibit), Maguba (Dallas gorilla exhibit), and Bibi and Ernie (Cheyenne Mtn. gorilla exhibit) were transferred from Denver to very different situations in terms of social group, habitat, and husbandry.  And yet the directions of change in their behaviors (see table) were virtually IDENTICAL - decreases in feeding, solitary play, and social interactions; increases in locomotion, abnormal behaviors, self grooming, and idle time.  There were only three exceptions, highlighted in the table.

Joe and Maguba both exhibited new stress-related VOCALIZATIONS, and they both developed new HEALTH PROBLEMS.  Joe's health issues were clearly related to his new environment. Maguba developed a persistent abdominal abscess, like Bibi had, which may or may not have been related to her transfer.

The changes discussed above strongly infer a decrease in the PSYCHOLOGICAL WELL BEING of all four gorillas.  The commonalities suggest behavioral changes that will likely occur after a gorilla is transferred.  These behaviors could be monitored to determine how a transferred gorilla is adjusting to its new environment.  

Results suggest that the BEHAVIORAL REPERCUSSIONS of gorilla transfers are likely to be dramatic and may be negative.  Gorillas are neophobic and are the most sensitive of the great ape species. These data suggest the utility of QUANTITATIVE STUDIES in monitoring the behaviors of transferred gorillas.