The Museum of Nature & Science (MoNaS) is located in the heart of historic old downtown Las Cruces, New Mexico, the state dubbed as “The Land of Enchantment”. The museum’s spacious floor plan, contemporary designed cases, detailed educational and interactive exhibits, and unique collections offer a memorable experience to the visitor. The museum hosts two of the most famous Permian-era fossil trackways, which are animal tracks frozen in the mud.
The Las Cruces MoNaS aims to inspire the visitor’s curiosity about the sciences, and features exhibits of the natural environment of the Chihuahuan Desert and southern New Mexico. There are three primary permanent exhibits: Desert Life, Light and Space, and the Permian Trackways. All text and labels are both in English and Spanish. The MoNaS is part of four museums that belong to the City of Las Cruces. Admission is free to all four museums.
The Permian Trackways
The tracks were preserved in the mud at the Robledo Mountains of Southern New Mexico. They were discovered in 1987 by amateur paleontologist Jerry MacDonald who excavated there for the next seven years. He used pry bars to lever apart the fossil slabs. MacDonald hauled out tons of rock (2,500 slabs) in order to share his discovery with the world. He carried many of the slabs — some weighing over 100 pounds — on his back for half a mile to his vehicle. Some of his excavation tools are also displayed at the museum.
The exhibit explains that not all fossils are bones, but they can also be tracks. While the bones indicate the shape and type of animal, the preserved tracks give us information about the animal’s behavior – how it moved, where it stopped, and when it turned. The large trackways represent a single fossil layer, one of dozens, each recording a snapshot of life at that moment when the animals stopped at the mudflats to eat, drink, rest, and hunt.
The rock slabs of the second impressive fifteen-foot fossil trackway bear the actual tracks of a Dimetrodon. The Dimetrodon is an extinct genus of non-mammalian synapsids (tetrapod vertebrates), more closely related to modern mammals rather than reptiles. Scientists learned a lot by studying these trackways. While originally thought that his legs sprawled wide and his belly was close to the ground like a modern crocodile, they concluded that this carnivore was up to 13 feet long and had a more upright stance and gait. A replica skeleton with its large neural spine sail stands above the tracks. It’s a cast from fossil bones found elsewhere, as the conditions were not favorable to be preserved in the Robledo Mountains.
Other Exhibits at the MoNaS
Two media programs, interactive displays, and touchable trace fossils further explain the exhibits. The interactive exhibit titled “Look at ….layers” asks visitors to split the replica open and see the track left behind by the animal. The “Trace Fossils” exhibit demonstrates the variety of life forms that left behind their traces, such as tracks, burrows and body prints in the Robledo Mountains.
The surrounding exhibits show live animals living in the desert rivers, the bajadas (desert plains), and the sky islands – the isolated mountains that stand high above the surrounding desert plains. They are called sky islands because plants and animals adapted to these conditions and cannot easily move from one peak to another, creating micro-climates and environments.
Besides an eye-catching amethyst geode, the museum has two wonderful petrified wood pieces – a large standing log with polished top surface and a sizable flat round slab hanging on the wall, both from Arizona, a gift from the Zuhl family. A large collection of petrified wood is on exhibit at the Zuhl Museum, also located in Las Cruces. A lot of petrified wood has been found within the Prehistoric Trackways National Monument, but collecting there is not allowed. A cast fossil replica of the head of Stan – the Tyrannosaurus Rex skeleton from the Hell Creek formation in South Dakota – stands next to the petrified wood exhibits.
The Prehistoric Trackways National Monument
The two Permian-era trackways at the Las Cruces Museum of Nature and Science were discovered in the Robledo Mountains, at 4,500 feet elevation, in Doña Ana County. Today, that site is part of the Prehistoric Trackways National Monument, a U.S. Bureau of Land management (BLM) site located approximately seven miles northwest of Las Cruces.
The Monument was established in 2009 “to conserve, protect and enhance the unique and nationally-important paleontological, scientific, educational, scenic, and recreational resources and values of the Robledo Mountains in southern New Mexico”. The site covers about 5,280 acres and includes a major deposit of Paleozoic Era fossilized footprint mega-trackways containing footprints of numerous amphibians, reptiles, insects, plants, and petrified wood dating back to 280 million years. Viewing of the Trackway fossils is limited, and there are no developed interpretive sites. To reach the Prehistoric Trackways National Monument a 4WD vehicle is required for the final mile (www.blm.gov/visit/ptnm).
Some of the trackway fossils are also located at the New Mexico Museum of Natural History and Science in Albuquerque, part of the Jerry MacDonald Paleozoic Trackways Collection. Tours there are available by reservation.
Getting There
The Las Cruces Museums of Nature and Science is located at 411 Main Street in Las Cruces. It is open daily except Mondays. The museum holds annual fests for kids and several weekly programs. For hours, parking and a video visit them at Museum of Nature & Science | Las Cruces, NM (las-cruces.org) Tel. 575.522.3120
All Photos © HelenSerras-Herman