We’ve been inside the park for a little while now, and you might be wondering … where are all the Joshua trees?
Be patient, they’re coming soon! You see those distant mountains on the left? We’ve got to get allllllllllll the way over there, where the elevation is a little higher, to see them.
And what is a Joshua Tree, anyway? Joshua Trees, A.K.A. the Yucca brevifolia, are incredible plants. Lots of people think they’re a cactus, but they’re actually a kind of succulent, and part of the yucca family. They can range in height from just a few feet tall to as much as 70 feet. Pretty impressive for an extreme climate, huh?
If you’ve never seen one, they have these weird, bendy branches, and at the end of each one, is a tuft of leaves that sorta looks like the top of a palm tree. When flowering, they produce beautiful cream-colored flowers on the ends of long stalks. I think they’re pretty cool, but I guess we can’t all be impressed. In 1844, early California explorer John C. Fremont gave a somewhat scathing review of Joshua trees when he wrote, “...their stiff and ungraceful form makes them to the traveler the most repulsive tree in the vegetable kingdom.” Roasted!
Do you remember earlier in the tour, when I said that Joshua Trees depend on an extinct giant? Turns out, there’s a very interesting link between these quirky trees, and an extinct creature called the Shasta Ground Sloth.
The Shasta Ground Sloth was related to the sloths of Central and South America that are still around today. Only instead of being the size of a large cat, this one…was about as big as a cow.
And just like a cow, the Shasta ground sloth was a vegetarian. But it didn’t only eat grass. It ate just about anything it could find. Including…Joshua tree seeds.
So, why did that matter? Well, Joshua Trees have to make trade-offs to live in this harsh climate… and one of them is that it doesn’t spend energy spreading its seeds. They just drop on the ground, and stay there.
But here’s where the friendly sloth came in, Hoovering up any food it could find. They would eat the seeds, keep walkin’ for some miles, and a while later – sorry for the potty talk – the big ole sloth would poop the seeds out, often miles away from the parent tree.
Pretty good strategy, right? Make your seeds tasty, and then let the animals do all the heavy lifting! Unless... that animal you depend on goes extinct.
Sadly for the Joshua Tree, the last shasta ground sloth kicked the bucket about 13,000 years ago, and left the poor tree without any effective way to spread its seeds far and wide.
Since then the range of the Joshua Tree has been shrinking, year by year. But for the moment, the Joshua Tree is still going strong here in the park.
You know, there’s actually a name for these kinds of plants, that have lost the animal species they depend on. They’re called anachronistic plants.
But that’s only half the story. There’s a whole ‘nother species the Joshua tree depends on!
Turns out, the Yucca moth has an incredible role in fertilizing the Joshua Tree flowers. When it’s ready to lay eggs, the moth will find only unpollinated flowers and lay its eggs in them. Then, get this, the moth pollinates the flower itself. Why? So that when the eggs hatch, the larvae will be able to eat the flower’s seeds. That’s a wise mama!
Now, if you’re feeling sorry for the Joshua tree, guess what, you can pretend you’re a sloth yourself! You don’t have to eat Joshua tree seeds - please don’t - but you can pick up some seeds, and drop them somewhere uphill. You probably won’t do it as well as a shasta ground sloth, but it will do. If you wanna help the seed even more, find some brush or a cholla cactus, and put the seeds at its base…that way the plant gets hidden from hungry jackrabbits and has a better chance of survival. Just remember that you’re not allowed to remove seeds, or anything else, from the park.
Explore Joshua Tree on Shaka Guide's Joshua Tree National Park Tour!