Between the March and April Portal trips, I fell through the looking-glass into the Namib Desert. Everything there felt so eerily similar to southeastern Arizona, yet also strikingly different. Compare the below photos from the Spitzkoppe, a large granite massif of volcanic origins in the western Namibian Desert, and of Portal (the Chircahuan mountains also are eroded granitic domes with volcanic origins!).
Spitzkoppe, the “Matterhorn of Namibia”
Chiricahua Mountains, with the Portal Project in the foreground, October 2007
Although I didn’t actually get to see or handle any small mammals while visiting the Spitzkoppe, there are diverse rodent communities in the Namib desert, as there are in southeastern Arizona.
Unidentified small mammal hole, Spitzkoppe.
Banner-tailed kangaroo rat (Dipodomys spectabilis) hole, Portal.
Both Portal and the Spitzkoppe are arid grassland deserts on the edge of small, isolated mountains. Both have acacia shrubs with white thorns, and both abound with spiny and woolly vegetation. However, Namibian shrubs are inhabited by weaver bird nests rather than cactus wren nests (but both are roundish with small, circular openings).
Weaver bird nests in an acacia, Spitzkoppe.
Cactus wren nest in a cholla, Portal July 2009
The large, eroded granite rocks are similarly enticing, easy to climb and explore, and also host populations of small cryptic scorpions, spiders, rodents, and lizards, although in Namibia, unlike Portal, you are likely to see groups of hyraxes. The surrounding plains are home to a variety of antelope and grazers (such as springbok, hartebeest, zebra, warthog and rhino, to name a few) rather than Coues white-tailed deer or javelina.
A very cryptic Agamid lizard, Spitzkoppe
Texas Horned Lizard, Portal (Photo courtesy of R.P. O’Donnell, May 2011)
Hyraxes are NOT large rodents, but are actually more closely related to elephants! These are Rock Hyraxes (Procavia capensis).
Euphorbia virosa, “poison tree”, in the Spitzkoppe. Although it looks similar to organ pipe cactus, this is NOT a cactus, but a member of the spurge family.
Experiencing another, similar desert was an amazing experience which I hope to repeat, but I eventually crossed back to my hemisphere and the right side of the looking-glass, where my world was again familiar and the research at Portal was waiting for me to return…In late April, we captured our first pack rat (Neotoma albigula) since Fall 2009 !
Sarah documenting the Return of the Pack Rat.
There was no rain between March and April, so the vegetation was all going to seed and the soil was dry and dusty again. Rodent abundance and diversity continues to rise, however, so they must be caching all those valuable little seeds!
Nic Kooyers, a graduate student at Washington University in St. Louis, came to learn about the project and look for unique desert vegetation. Nic is especially interested in the evolution of plants that display variation in the production of secondary compounds, but he really liked the rodents, too.
Nic weighing an Ord’s Kangaroo Rat (Dipodomys ordii).