More outback than jungle, with deep canyons cut in to sandstone rocks, Isalo offers a huge contrast to the verdant eastern rainforests.
While it is possible to hop on a charter and fly in to Isalo you're likely to appreciate the contrast a great deal more if arriving by road from the north - but either way there is the option of staying one of a couple of the islands best lodges here.
The wildlife is less concentrated in Isalo than some of the other parks, but the variety of landscape, birdlife and some incredibly nonchalant ring-tailed lemurs and sifakas all make for excellent photographic subjects.
There is a feeling of liberation to be able to take a full day hike and work up a bit of pace, after days of creeping through the rainforest peering in to the gloom. With the sun on your back pretty much guaranteed in the summer months, this feels more like Australia or Africa without the scary stuff (snakes occur, but as with all Madagascar's serpents they are all totally harmless to humans) and there are several circuits of various lengths, complete with natural pools for a welcome cooling dip.
Isalo is a great place to spend a couple of nights if making a road trip through the southern half of the country - it's fairly easy to get here from Ranomafana in a day, stopping off at the excellent Anja Community Park if you can. If continuing down the road toward the coast you pass through real wild-west country, centre of the country's sapphire mining boom, before hitting the rewarding little Zombitse-Vohibasia National Park - the transition zone between the limestone massif (Isalo) and the Spiny Forest further south - with great lemurs, birds and the Za Baobab.