The first point of interest is Junction Cave right at the trail head. Junction Cave is a lava tube created by lava flows from nearby El Calderone cinder cone and is thought to be 115,000 years old. Junction Cave can be entered if you are properly equipped with hard hat, gloves, and at least three flash lights.The interpretive guide discusses the types of life that use caves, with most of it being very small species. The cave information indicates that there is at least about 500 feet of tunnels here.
Another feature is the Double Sinks, the trail passing right between two very large holes, each about 80 feet deep. The terrain here is a bumpy lava surface covered with grass with scattered pine and juniper trees. There are both Pinon Pines and Ponderosa Pines.The lava tubes and trenches have an effect on the environment in that water runs off collects around the edges, making the edges moister than they would be otherwise. The extra moisture allows better growth in specific spots.
Bat Cave is another of the highlight features. Bat Cave is also a lava tube and provides habitat for several species of bat. The Mexican Freetailed Bat uses the cave in the summer and migrates south for the winter. Little Brown Bats, Pallid Bats, and Townsend’s Big Eared Bats are year round residents. There is an interpretive sign here that mentions that bats can eat up to 600 mosquitoes per hour. The world has about 900 species of bats with 10 having been found in El Malpais. (In 2011, the bat caves of El Malpais have been closed to recreational use due to the fungus associated White Nose Syndrome bat illness that has been spreading across the country.)
There were at least two eruptions at El Calderone. One created the black cinders and the other created the red cinders. The red cinders contain a higher amount of iron. The trail guide mentions that lava bombs up to three feet in diameter were hurled from El Calderone and can be observed along the base.
The crater of El Calderone has a good growth of Ponderosa Pines. The trail into the crater runs along a long lava trench that exits from the side of the crater. I walked this 3 mile trail in about 1:15 hours, but I was in a hurry as there was a summer thunderstorm threatening. The route is smooth without much elevation change and is graveled part of the way. It was an 80 F late June day and I drank a liter of water when I finished, after not drinking any during the hike.
