In the US, it’s Jackson by far in the lead, followed by Mabu, and in a VERY distant third, Maclean.
Jackson has nine kids and 10 grandkids (some of which are currently fetuses still), Mabu has 15 kids, two of which are still fetuses, and Mac has 4 kids. Bulwagi three kids, Sdudla three kids, Ali two kids one grandkid, Titan two kids, Tendaji one kid. Deceased Willy has two kids.
pretty poor founder rep, huh?
This underlines that the management for the African elephant population in North America (AZA/beyond) as yet requires very careful planning now and well into the future with regard to growing the population exponentially while at the same time dealing with an ageing non reproductive cohorte of its population. This policy no doubt must keep a very close eye on levelling out founder representation and increasing genetic diversity and while slowly also replacing current set ups to a division into breeding herd locations, other zoos with bachelor facilities to house bulls only and zoos where only non-reproductive cow herds are to be held.
This is likely a process that will continue for another 2 decades and a 10-25 years time frame into the future to stabilise the current African elephant population given that natural elephant reproduction will see reproductive age cows only calve once every 4 to 6 years and consequent slow growth rates and long generational lengths to replace the current partially reproducing and good part not reproducing population.
Reproductive output
Short-Term
For now, the program needs to maximise the current reproductive output fast(er) and would have to rely on the current crop of bulls (as named above) with as a short term / stop gap measure to have the current proven bulls to successfully mate and impregnate a good and hopefully large portion of the available reproductive age cows and add new calves and new generations to the population with more a positive future outlook going into the future.
I would assume that the program is also looking into how more effectively get better founder representation from the current proven bulls like Mac, Bulwagi and Sdudla with low representation in the current elephant population. This is very much a medium term policy and requires frequent moves / transfers of adult proven breeding bulls between herds with reproductive age and cycling cows.
Long-Term
Down the line there is a real need to get more as yet not represented new bulls of breeding age into a position / at locations where they have access to and are able to breed a good number of reproductive age cows. The prime strategy is to bring out young and teenager bulls from the herd they were born into transfer to a bachelor herd or another breeding group where they can experience an adult breeding bull accustomed to and cool with the cows in the herd that he mates.
Lastly, ample consideration needs to be given to the fact that you put 18-35 age range bulls into that breeding situation and don't misuse bulls under age or 18+ and not having had access to conspecifics or an experienced breeding bull at any one time with cows of similar age range or even with their own mother present in the herd (major social structure default).
First Evidence?
Callee is one of the first of the new bulls who does seem to have broken the stalemate (even though he is effectively an F1 from well represented sire Jackson). When taken as an pre-adult to Omaha Henry Doorly he has proven to be a very efficient breeder at Omaha (so much so that now he quite possibly has sired a good number of the cows at Sedgwick County Zoo).
But of course, there is a need for far more young/new bulls of his stature to breed in the future: Titan may be a future possibility (but not in the herd where is mother Simnunye is still present) and he really needs to be moved out from there ASAP to a bachelor herd or a location where he can meet new young reproductive age cows or for the maantime to a herd where he has conspecifics of his sex and age range (in other words new bachelor herds are urgently needed).
Bachelor herds
ATM: there is only just the one dedicated bachelor herd facility at Birmingham Zoo. That is a situation that should not persist: At least 2-3 more zoos need to be found now and well into the future to house growing teenagers / not yet reproductively well suited growing bulls.
San Diego Zoo has not too long ago sent two of its Wild Animal Park bred young bulls over to the San Diego Zoo with F Shaba (non reproductive). Not sure if they have sufficiënt space they have though to house any further bulls on site. Caldwell Zoo seems to also have moved in that direction with 2 other San Diego bred bulls maintained with a non-reproductive older cow on site.
I honestly do think that bulls like Titan (Sedgwick County - Wichita), Samson (Baltimore) and Vus’musi (San Diego WAP) would obviously benefit from a move out of their birthing herd to a different zoo with more favorable sex/age ratio in terms of cows as I predict that in the current constellation with their both their mothers and much older experienced cows in their herds they will probably never breed.
Non reproductive cows/ageing cow herds
Quite a few herds within AZA have non reproductive cows and the population is offcourse ageing with a good number in the age classes wildcaught in the 70's, 80's and 90's. It would be best if with the local social structures in mind these herds are concentrated more in places that definitely see no opportunities to realistically provide for a breeding herd (quite a few are large and hold 4-7 members at least). Examples like Colorado Springs - Cheyenne Mountain and Memphis Zoos.
Zoos with a mix of both non reproductive and reproductive cows
(with no access to a bull)
Some of these zoos with older age range may have 1-2 cows of breeding age (the 10-20/25 age range) with some potential yet with no access to a proven bull or one in the right age class with non mother present. Not quite ideal either as they are part of a larger group with its own dynamics in social structure and who is the matriarch or not. Maryland Zoo, Baltimore (, Montgomery and Pittsburgh Zoos comes to mind. Some of these have been languishing at the paucity of any attempts to get their cows to breed naturally
The ideal of course would be a system of bulls being sent on B/L to a zoo to mate with their cows - if they cannot hold a bull permanently - and have him move on when he has got the job done and the cows have the room to roam much like they would in the wild.
Behavioral and mechanically non-breeding bulls
This subject has been partially dealt with here and there. For example bull Ajani (sent up from Sedgwick to Toledo) is cited as a possibly to be one and as is bull Osh at Oakland (where I believe the social structure with him as immigrant very kuch younger bull in a much older range cow social dynamic was hardly conducive to him becoming a breeding bull).
For now, I let this subject lie as I would need to check up why some bull combinations have failed and why. In / out of this category there are quite a few bulls that might do / don't fit into this category. I am convinced though that some of the non-breeding or deemed behaviorally maladjusted bulls may be more to do with social dynamics, stressors in their husbandry and simply an unnatural/sub-optimum social structure that are impediments to them breeding.
POST SCRIPTUM:
I have not yet taken into account how or why the reproductive potential for some of the bulls I mentioned (Bulwagi Mac, Sdudla) is as yet so low or that they may have sired further calves in the meantime. What is certain that the last word is not be said about this subject.
I would also like to delve a little deeper into why some cows do not breed as others do wthin their current social structure. I do believe there is an element where near siblings will not breed or at least one or more are suppresed by more dominant siblings from breeding. For now, that is just an inkling I get from similar evidence from other pachyderm species, notably rhinos.
