Heart Disease in Captive Male Gorillas

[Buckeye092]

Overview: In the past forty years a steadily increasing number of male gorillas have been dying from heart conditions. What is scary is the most recent deaths have been in younger gorillas. These conditions appear genetic and within the next few years the US captive gorilla population could be depleted of males.

Heart Conditions: There are a number of heart conditions that gorillas are suffering from, one of the most common being cardiomyopathy. However the general problem is that the heart size increases and parts stop functioning reducing efficiency of blood flow. (For those who are wondering: a gorilla's heart is actually fairly similar in size to ours and the structure is the same, the only difference is that it is slightly larger)

The Solutions: Not surprisingly, some solutions to help these heart conditions include medications like Coureg. Some zoos are also experimenting with pacemakers. However we still don't know what is causing these problems some we can't help all the gorillas. And we're still losing gorillas.

Also the AZA, gorilla SSP, and multiple universities are conducting studies on this issue but their results won't be in until next year.

Thoughts on this topic?

 

[Pertinax]

Thoughts on this topic?

Its a fascinating one!

I've been watching the steady increase in losses in male Gorillas (it is almost entirely Males) in captivity from heart-related problems over several decades. I've noticed that it seems more prevalent in American Zoos than European ones- or at least I have seen more reference to animals suffering from these problems in the USA. There have been some heart -related deaths in Europe though perhaps not so many as in US. Also I don't know of any European males being fitted with pacemakers or given other medication for heart-related problems.

Historically, heart problems seem to have been contributing to male Gorilla deaths for many years. The first I ever came across was at Bristol Zoo in 1968. Their 18 year old male 'Congo' was considerably overweight and died of an 'Aortic Aneuryism' (=Heart Attack?) He had lived alone for two years but could see a much younger pair nearby who had started regularly mating. The onset of their sexual behaviour may have excited/stressed him and brought on the attack as he died very suddenly- just keeled over at the front of the cage one day.

The famous male 'Jambo' at Jersey Zoo died similarly of a similar condition- Aortic aneuryism. He was aged 31. In Humans this condition occurs in the 40-60 year age group and is 2/3 times more common in males apparently. Hypertension is said to be a contributing factor and I think the most likely cause in captive male Gorillas. In Jambo's case there was no obvious cause or aleration to his routine beforehand, but perhaps in some cases their lives involve a lot more stress than is apparent on the outside?

In 2006 Twycross Zoo (UK) silverback 'Mamfe' (son of Jambo above) died at a similar age(33) to his father. In his case there was a significant change to his routine before his death. A strange pair of gorillas including an older silverback 'SamSam' had recently been moved into the adjacent enclosure and the two males could see each other directly. From years of quiet living(with only the very old and familiar male 'Joe' next door), Mamfe was suddenly faced with a new 'rival' and his behaviour changed dramatically. Obviously upset, he started displaying and 'guarding' his females from the 'interloper' and after a couple of months of this, Mamfe suddenly died 'from a heart attack'. I strongly believe it was brought on by the soaring stress levels and increased activity caused by the arrival of the new male next door though it could have been a genetic cause too. Its interesting to note that Mamfe's grandfather 'Stefi' died at Basel Zoo age 32 also, so that is three generations; Stefi- Jambo- Mamfe who all died at almost exactly the same comparatively early age. The early thirties does seem, at least till now, to be the age at which Gorilla males have been most susceptable to this cause of death.

But its also a major concern the age for these heart-related problems seems to be getting lower too. I cannot explain that but it seems an increasing problem for male gorillas in some zoos, more particularly in the USA.

 

[Buckeye092]

Unfortunately the descendants of Columbus Zoo Gorillas (which are now all over the country) seem to be of the family trees that is prone to these conditions. Here's a little history:

Baron Macombo - WB 1946 - Died 1984 (Heat Failure) - 38 years old

Bongo - WB 1957 - Died 1990 (Heart Disease) - 33 years old

Oscar (Bongo's Son) - CB 1969 - Died 1993 (Heart Failure) - 24 years old

Sunshine - CB 1974 - Died 2008 (Heart Disease) - 34 years old

Jungle Jack (Sunshine's Son) - CB 1987 - Died 2008 (Heart Disease) - 21 years old

As for our current three adult males, Anakka has it the worst (weird because both his parents are WB) Macombo has it the second worst (scary because he is 24 and his dad is Oscar) and our 43 year old WB male Mumbah has it but it is moderate compared to Mac and Anakka.

What other gorillas have died in the past ten years in the US and Europe from heart disease?

 

[Pertinax]

I'm sure you're aware that Stefi(Christopher) at Basel Zoo whom I mentioned above was one of the three Gorillas originally imported to Columbus? I feel sure he and Colo's mother Christina/ Millie came from the same wild troop and as such were closely related, possibly half brother & sister or closer still. 'Stefi' and 'Colo' had a striking facial resemblance to each other and I reckon he was her 'uncle' - so all his European descendants are probably related to Columbus' lines too!

Regarding Heart Disease- your list of males is very interesting. I'm wondering if there really is a genetic link, or more simply that the stresses that induce these problems are common to many males in captivity. So it may seem genetic because some of those that die are related to each other, whereas that might just be coincidental and the real causes aren't genetic at all?

Certainly there are several European males which have died at what seems like a premature age (Bongo Apenheul, Bitam Howletts, Djoum Port Lympne etc) but apart from the ones I mentioned originally I can't be sure of others but I've p.m'd Yassa about this as he knows the European Gorillas well. And I'm not aware of any males which are showing current evidence of any heart problem/disease in European Zoos- but thats not to say there aren't.

 

[Sun Wukong]

Didn't someone of the vet staff of the New England Zoo work on that subject a few years ago?

 

[Yassa]

Hi guys, I was away for the weekend so I had no time to look for the information I needed to answer Pertinax question. I remember only one male in Europe who died from heart disease in the last years - Derrick/Berlin Zoo. He was 25 at death. Thankfully, there is no history of heart disease in his family tree, since his father was Matze who died just recently as oldest captive male gorilla ever, age 52 (I believe). His mother is wildborn and still alive too, the fate of his maternal grandfather is unkown, obviously.
Bongo died from a bacterial infection which is normally not dangerous, but it is believed that the stress of living together with his teenage son weakened his immune system.

I don`t remember any other males suffering from heart disease in Europe - I can`t see a pattern like in the US with more and more males dying from heart disease in European Zoos. However, I hope the US zoos don`t continue to breed with males who have been diagnosed with a heart problem, regardless how important they may be genetically.

I have just done a ton of research on the mountain gorilla groups studied by the Karisoke research centre founded by Dian Fossy (to find out more about bachelor groups in wild mountain gorillas) and what haunted by was how low the life span of wild mountain gorillas is - both male and females. This year, famous silverback "Pablo" (born in 1974 in group 5) vanished and is most likely dead at age 34. He was the second oldest male gorilla in the study area!! The oldest male is Titus, born in 1974 originally in group 4, who is just a bit older then Pablo. The females seem to become a bit older but a female older then 40 is considered ancient old, with most dying from natural causes between their early 30`th - 40.

 

[Buckeye092]

Rememer: Of all five gorillas subspecies, Mountain gorillas have the lowest life expectancy. We are not sure why but some scientists attribute it to the higher elevation at which they dwell.

Good News: A small treaty made between the Democratic Republic of Congo and the rebels (who have been fighting a civil war for some years now) will allow researchers into Virunga National Park (which holds 1/3 of the world's population of Mountain Gorillas) to conduct a census, after the rebels had stormed the park a month ago and forced all the rangers to evacuate.

 

[Pertinax]

I don`t remember any other males suffering from heart disease in Europe - I can`t see a pattern like in the US with more and more males dying from heart disease in European Zoos.

This is what I thought- there is evidently a higher incidence of heart related problems in USA Gorillas. We have them in Europe but they appear to be much scarcer. Why?