Evening star., 1932-06-02
RATS BUILD HOUSES
IN SOUTHWEST j. s.
Monograph Tells of Unusual
Small Mammals Found
in New Mexico.
BY THOMAS r. HENRY.

BY THOMAS r. HENRY.
Rats that build houses are described
in monograph on the mammals Of
New Mexico just issued by the Biologi-
cal Survey.
These creatures, according to the de-
scription of Vernon Bailey of the sur
vey staff, are native ratlike animals"
constituting an entire subfamily in the
mammal kingdom with 10 species and
subSpecies. They were discovered scien-
tlflcally by DR.. c. Hart Merriam Of
washington and several of the species
were named for him. The animals
range over a wide area in the South
west and most Of them we're eaten by
the Indians. Their flesh i- very good,
says Mr.. Bailey. and if they were larger
they would be valuable game animals.
Their houses" are of all sorts and
materials. varying somewhat with the
species. Perhaps the most conspicuous
member OF the family is the hoary wood
rat. which builds in the midst of prickly
pear beds houses which are usually
cOnical in form, 3 or feet high, and
about as wide at the base" Such
house may stand in the open and is a
veritable fortress, the material of the
walls being held together bv thorns
which protrude through the sides. Such
houses usually are SO well built that
they seldom are broken into by enemies.
Others are built around thorn bushes.
They may have several rooms. One
house examined by Mr.. Bailey was COM
poced Of dried balls Of mud, sticks and
bones and lot CT discharged shotgun
cartridges. Some houses are entered by
a half dozen doorways. leading TO in
ternal chambers both above and below
the surface of the ground Bailey tore
apart one of these houses and found
the chambers perfectly dry. although
there had been hard rain the previous
night.
Use Much Material
Almost as expert builders are the
white-throated wood rats Of the same
family. They erect their homes either
in thorn patches or among the rocks.
adapting the building technique to each
locality. Shallow caves IN cliffs are
their faVorite Strongholds anS in some
of these, Bailey found. the rats have
gone on building Up their piles of thorny
rubbish until they have astonishing ac-
cumulations. Caves containing from 20
to SO bushels CT material which the
rats have carried in bit by bit are not
uncommon. Sometimes the animals
throw up thorny barricades TO prevent
larger animals from penetrating to the
nest chambers back in the rocks. A
house of one of these rates, Bailey says.
often rises in peaked dome or 3
feet high and as wide across the base,
with numerous doorways at the sides or
underneath the edges. If occupied by
vigorous family such a house rises
with the accumulation of constantly
added material into a higher and
sharper peak.
The building material used by the
rats Is dependent on what is available
in the vicinity and varies endleSsly.
Sticks stones. bones, horse droppings.
thorny branches and shells OF various
fruits and seeds are the most common
materials used. Stray articles found
about camp sites are taken-fork5,
spoons, pieces of dishes, bits of cloth
and rope The internal structure Of the
house varies somewhat. but usually con-
sists of one or several rooms or nest
cavities. sometimes all above the ground
and sometimes all below the surface.
The nests are usually of finely shredded
bark. are often thick and warm, and
usually are soft and clean. Sometimes
they are covered over, but more often
are open ard cIo-snaped like a robins
nest. just large enough for the rat 20
curl up in. some OF the house cham
bers are filed with food OF various
kinds brought in TO be eaten at leisure,
or stored for future use.
Are Expert Climbers.
These rats are expert climbers.
Much Of tleii icod is gathered from
bushes. trees ana vines and occasionally
they are found living in hollow trees.
| have shot them in oaks 20 feet from
the ground. They climb the spiniest
cactus trees and run oyer the thousands
of needle pointed spines without the
slightest inconvenience. notwithstanding
that the soles of their feet are as naked
and delicate as the palms OF ones
hands"
DR.. Z. A Goldman Of the Biological
Survey found a house of another species
of this family which was built of will
low and wild rose sticks and hop vines
and was more than 10 feet in length.
Still others build entirely by heaplng
up the Splny pads of the local cactus
bushes.
Even more remarkable are the bushy-
tailed woodrats which live in an open
desert country and build sturdy nests
of rocks. Some of these nests are
made of fiat pieces of sandstone from
four to five inches in length and con-
sderably heavier than the animal itself.
They supplement these with sticks and
thorns
These creatures were found especially
abundant in the ruins of the prefis-
tOTic Pueblo Bonita. where they seemed
to have taken over the adobe structures
abandoned by man many centuries ago.
They probably were serious pests to the