Dear @SafariChick and @Tom Kellie, thank you for your kind response! As far as we can tell now, desert warthogs are not more relaxed around people then common warthogs are....but there is a lot to learn about them so we keep our eyes open of course. In areas warthogs are not hunted both species can get habituated to the presence of vehicles etc. We have seen both taxa very wary of people in areas we believe they are hunted (north and western Kenya particularly).
As you probably know, common and desert warthogs are sympatric in both Samburu and Meru. It is possible that you saw both species during those trips Tom!
Your requests and posts are certainly timely and thought-provoking.
As it happens, one of the primary riddles during my Kenya safaris has been warthog identification in both Meru and Samburu.
Both in the field during game drives — my guide, Anthony Gitau, tends to take me to more remote corners — and back home in Beijing, looking over safari photographs, there's been a sense that I might be observing two different species.
That feeling is based on looking at tusk curvature, bristle distribution, and general demeanor.
I've wished that I could have advanced specialist field training in warthog identification in order to distinguish the species, especially as I'm especially fond of visiting both Meru and Samburu.
It's a priority on my to-do list to scrutinize numerous warthog photos with field guides open, in an attempt to train my eye to key visual distinguishing characteristics.
Your work is highly appreciated, as it involves an under-appreciated yet richly deserving species.