Essays

Moseying: Exploring the Natural World

Introduce yourself to the kangaroo rats at the Monahans State Park
July 26, 2006

I like kangaroo rats! And especially Ord’s kangaroo rats, to be specific. They are so cute – they are beyond cute! They are easy to see, if you are in the sand dunes between the hours of 10 p.m. to midnight, or 4 in the morning to daybreak. If it is during a full moon, the rats do not emerge unless they have run low on stored seeds. “They don’t give a hoot” if you shine a flashlight at them. If you have a supply of cashews they will keep coming back until you run out. Go camping at the Monahans State Park and introduce yourself to one of the most fascinating creatures in the world! Take some digital pictures of their antics – the Sibley Nature Center would love to showcase your pictures for the world to see!

At the Sibley Nature Center we have Merriam’s kangaroo rats, and in the tight clay soils along the Pecos River bannertail kangaroo rats thrive. The Merriam’s has one entrance to their den, which they close every morning. The bannertail builds a huge mound with dozens of entrances that remain open. The Ord’s entrances also remain open, too. Bannertail mounds are inherited through countless generations, but individuals of the other two species always build their own.

In the dunes, the tracks of the kangaroo rats tell the tale of their night’s work for all to see every morning. I love the mental challenge of ferreting out the solution to the mystery of “just what did this one do.” It is a wonderful way to put the worries of everyday life on hold – to get mentally swept away in understanding another creature is a blessing. One animal lover I know, a devout Christian thoroughly involved in her church, told me once, “I believe that one of the reasons that God created the creatures is to teach us to see through the eyes of beings far different than ours. In other words, we learn the art of empathy by observing and understanding other creatures. Observing pets is where you start, but observing wild creatures is graduate school in empathy.”

For years the Sibley Nature Center has collected information from scientific papers and popular magazine articles and we recently dug through the kangaroo rat folder while preparing our new Sanddune Ecology and History displays. Kangaroo rats are cool! Early biologists discovered that kangaroo rats do not need to drink water. They can survive on eating nothing but dry seeds. This amazing and baffling fact intrigued biologists, so the genus has been the focus of many masters and doctorate theses.

The adaptation of organisms to their habitat and the interconnections between the organisms within one habitat is utterly fascinating. For example, the seeds of the plants of the sand dunes germinate with greater success if they have been in a kangaroo rat’s mouth. There are two fungi in a kangaroo rat’s mouth – one is saprophytic, or in other words, an agent of decomposition. This fungus erodes the outside surface of the seed so germination occurs more easily. The other fungus in the rat’s mouth is mychorrizal. This type of fungus sends out hyphae that extend beyond the tip of root hairs of a plant and allows it to gather nutrients from the soil. Since kangaroo rats gather and bury their food for later retrieval when the stores in their burrows run low, seeds are often left behind when a predator kills the rat. Those “stored” seeds then germinate. What a wonder! Maybe we should all have a kangaroo rat to treat our garden seeds!

In the burrow, a kangaroo rat manages the stored seed. They monitor the growth of mold and fungi on the seeds. If there is not enough mold or fungi, they will move it to a more humid section of the burrow. To increase the humidity, they will close off a section of the burrow. If there is too much mold and fungi, they move it to a drier area.

When they collect seeds the mouth is stuffed full. The mouth is a modified structure – there is extra skin that forms pouches so even more seeds can be carried. When they return to the burrow or to their seed cache, they hit their face to pop out the seeds. They slap themselves silly – and do it so quickly that the seeds fly out like the bullets out of a machine gun. I would love to see that! I would love to have a video of it! Although grass seed is their preferred food, they will also eat poisonous seeds, such as cocklebur and moonflower, and irritating seeds like goathead and caltrop, which are covered with spines. Up to ten pounds of stored seed have been found in one burrow.

Kangaroo rat kidneys are the ultimate recyclers. In digestion, as the sugar in the seeds is broken down in their body, hydrogen and oxygen are byproducts of the process. The two elements combine into metabolic water. Their feces are hard and dry, and when urine emerges from the body it immediately crystallizes. The nasal passages of kangaroo rats are as convoluted as a pile of spaghetti and lined with mucous cells and hair. Every drop of the moisture of respiration is collected and returned to the body. The air in the nasal passages remains at 45 degrees Fahrenheit, which also helps the moisture to condense and be reabsorbed.

Kangaroo rats communicate by thumps. When two meet they both thump the ground with their hind feet. Except during mating season the usual result is a dirt-kicking fight – they jump back and forth sideways. If a human thumps the ground with a forefinger, sometimes the kangaroo rat will respond and thump back. Thumping at the entrance to a burrow will sometimes result in an answering thump, and sometimes even result with the emergence of the rat (at night, when it is present.)

If anybody has ever kept a kangaroo rat in a cage, the staff at the Sibley Nature Center would like to hear about it. We would love to find some one willing to capture one, design a natural-looking terrarium with sand, rocks, and plants, and then photograph the creature for our website.

Special Event: On August 26th The Southern Llano Estacado Chapter of the Texas Master Naturalists will hold the first of 8 daylong classes (once a month.) All classes will be on a Saturday. In addition to the curriculum developed by the Texas Parks and Wildlife Department covering basic ecological concepts and a review of statewide ecology, students will be introduced to the flora and fauna of West Texas. Instructors include employees of the Texas Parks and Wildlife Department and local experts. The cost is $75 or $125 for a couple. Field trips to ranches in the region are included. Call 684-6827 and ask for Burr for more details, or to reserve a spot in the class. Thank you, Sammy Hunnicutt of Big Spring, for spearheading the committee that met the requirements of the state organization so the class can be offered!