For anyone in the future viewing this photo, Stripes (the male shown above) is housed separately from the females (Twigga and Ginetta) as Ginetta is fairly geriatric (late 20's, maybe even early 30's) and therefore it isn't worth the risk of her possibly becoming pregnant at this age (her last calf in 2004 was stillborn, so it was decided that it was best to end her breeding days)
Just to clarify, all three giraffes are now housed together, Stripes has been observed breeding Twigga. Ginetta I believe is turning 29 this summer (I may be wrong).
