Probably not...but check out this article anyway for some interesting insight into the possibilities.
Testing the flotation dynamics and swimming abilities of giraffes by way of computational analysis
A few years ago, the excellent BBC series Big Cat Diary featured a scene where a group of giraffes tried to cross the Mara while it was in flood. The giraffes got about half-way across before turning back [two of them are at the turning-back phase in the adjacent still, © BBC], and at one stage were in water that submerged them right up to the bases of their necks. I thought at the time that these giraffes must have been swimming: I was so confident that I even mentioned this on the Dinosaur Mailing List back in 2000 (I now think it more likely that those Kenyan giraffes still had their feet on the riverbed: you can see this for yourself, as the footage is online here*). Several writers and researchers who have googled 'swimming giraffes' during the course of research have discovered my comment, and I've since seen it paraphrased in a few places (such as here at Telegraph.co.uk and on Focus magazine's Q&A page).