Although animal life isn’t the park’s most prominent feature, there's a good chance you'll spot the park's three diurnal lemur species: ring-tailed lemur, red-browed brown lemur and Verreaux's sifaka. Your best chance of spotting them is between 11am and 3pm from March to October at the campsite close to the start of the Namaza trail; it's an 800m walk in from the car park. These three species can also be seen at Canyon des Makis and Canyon des Rats.
The park is also home to three nocturnal lemur species: grey mouse lemur, red-tailed sportive lemur and Coquerel's giant mouse lemur, but as night walks inside the park are no longer allowed, your only chance of seeing these is to camp overnight at Namaza or Canyon des Makis campsites. Even then, chances are slim.
More than 50 bird species also inhabit the park, and birders get particularly excited here if they track down the Benson's rock thrush, Madagascar sand grouse, Madagascar partridge or the hooded vanga.
Near streams and in the lush pockets of forest in the deeper canyons, there are ferns, pandanus and feathery palm trees. At ground level in drier areas, look for the yellow flowering Pachypodium rosulatum (especially beautiful in September and October), which resembles a miniature baobab tree and is often called ‘elephant’s foot’.
The length of time the various circuits require depends on whether you take a car to the trailhead (which we strongly recommend). Otherwise you must walk in from Ranohira, which is a long way across hot, open country in most cases. Bring sunscreen, a hat and enough water for your visit. Picnic lunches can be arranged – ask your guide or hotel.
- Piscine Naturelle Short trek to a beautiful natural pool. One of the easiest and most popular trails, although there is some steep walking. Start early as much of the trail leads across open country with no shade. It's 3km by car and 3km on foot.
- Namaza A variety of possibilities but one of the more rewarding heads through deep gorges, taking in (at its lengthiest) the lemur-rich Namaza campsite, the pretty Cascade des Nymphs, a ridgetop lookout and two deep natural pools. The full trail trail runs 6km and takes three to four hours.
- Circuit Crête (Crest Circuit) Begins at the Piscine Naturelle (combine the two treks for a fine day walk) and then climbs up to follow the ridgeline with fine views en route. The trek covers 4km in 2½ hours and is of medium difficulty.
- Canyons Takes in the Canyon des Makis (aka Canyon des Singes), with chances of seeing lemurs, and the Canyon de Rats burial area. A 17km drive and easy 2km hike, taking around 2½ hours.
- Falls of Anjofo Hike by the river’s edge to two waterfalls. It's 29km by car, and a somewhat difficult 3km hike that should take around five hours, including the drive.
- Moyen Circuit This title is used by guides as a catch-all for a variety of longer hikes that can be full day or even two to three days.
- Grand Tour An 80km, six- to seven-day trek that takes in as much as the park can offer, including the Portuguese Grotto, a picturesque, 30m-long cave in the park's north. The way to get away from it all.
To make the most of your time in Isalo requires careful planning.
- Day One Combining Piscine Naturelle with Namaza gives you a good mix of landscapes and wildlife. If you're more interested in landscapes than lemurs, take the Circuit Crête instead of Namaza. And don't miss sunset at La Fenêtre de l'Isalo.
- Day Two Do whichever hike you didn't take on day one and add in the Canyons trail.
The Malaso 4WD circuit is primarily intended to provide a window on the park for those of impaired mobility. It leaves the RN7 south of town, although you'll still need to pick up a guide from the park office in Ranohira. The route takes you across the plains and broad valleys and to the edge of some canyons, with stops at some short trails. It's a 42km, four-hour drive with some optional walking.
Parc National de l’Isalo's MNP office has a list of the 72 accredited guides, along with the languages they speak and their phone numbers.
If you take your own vehicle to the trailheads, guides usually cost Ar20,000 per person per circuit. Example combinations include Piscine Naturelle & Crest Trail (Ar36,000), Piscine Naturelle, Namaza campsite and Cascade des Nymphs (Ar45,000) and Piscine Naturelle, Crest Trail, Namaza campsite, natural pools and Cascade des Nymphs (Ar113,000).
At two places, climbing aids have been bolted into the rock, scaling to the top for fine views. In both cases, you're provided with all of the equipment. The climbs are considered suitable for people who have never climbed before and those with basic fitness.
- Via Ferrata A 750m circuit around 27km northwest of Ranohira. The starting point is the same as for the Falls of Anjofo hike.
- Le Relais de la Reine This hotel offers a 1½-hour circuit up to the canyon summit for fine views. The climbing portion only lasts around 10 minutes, making it suitable for all fitness levels. It's open to non-guests and costs €20 per person.
Le Relais de la Reine has a small equestrian centre that is open to non-guests and is a fine option for exploring the canyons beyond the park. One-hour/half-day rides cost €15/50 per person, while children's pony rides cost €5/8 per 30/60 minutes. Longer expeditions into the park are also possible.
The park's MNP office rents out OK mountain bikes for Ar20,000/30,000 per half/full day.