People driving in Joshua Tree National Park are being asked to watch out for wildlife after the deaths of three desert tortoises in the past week.

Two of the tortoises were killed in a campground.

The National Park Service said Wednesday that factors contributing to the deaths include a big increase in visitors to Joshua Tree in recent years and the spring bloom that has drawn animals like the tortoise out to feed.

Desert tortoises are a threatened species that typically have 50-year lifespans in the wild, with some living 80 years.

Park officials say objects that may look like a rock or branch on a road could be one of the Joshua Tree's resident animals.