Published information on the food of _T. ornata_ consists of a few
miscellaneous observations. Cahn (1937:103) opened five stomachs that
contained partly digested vegetable matter but no insects or other
animal food: Ortenburger and Freeman (1930:187) noted that
grasshoppers were a main part of the diet of _T. ornata_ in Oklahoma
and that turtles displayed unsuspected agility in catching them. Those
authors also saw turtles eating caterpillars and robber flies.
Strecker (1908:79) stated that "The natural diet of this species
consists of vegetable matter and earthworms." Norris and Zweifel
(1950:3) observed the feeding habits of captive _T. o. luteola_.
Coyote melon (_Cucurbita foetidissima_) was eaten with reluctance but
a collared lizard (_Crotaphytus collaris_) was quickly devoured.
Tadpoles of _Scaphiopus hammondi_ were caught in a small pool and
eaten. Adults of the same species were rejected after being caught;
box turtles were seen wiping their mouths after rejecting adult toads.
The authors suggested that _T. o. luteola_ is an important predator of
_Scaphiopus hammondi_, since the two species occur together in many
areas and the emergence of both is controlled to a large extent by
rainfall. One individual of _luteola_ was seen eating a dead box
turtle on a road.
Captive individuals of _T. ornata_, observed in the present study, ate
nearly every kind of animal and vegetable food given to them. Table
scraps, consisting chiefly of greens, various fruits and vegetables,
meat, and cooked potatoes, formed the main diet of turtles kept in
outdoor cages.
A number of persons have told me of ornate box turtles eating the
succulent stems and leaves, and the fruits of various garden plants;
similar incidents probably occur in areas of native vegetation. J.
Knox Jones told me he saw an individual of _T. ornata_ eating a
spiderwort (_Tradescantia_ sp.) in Cherry County, Nebraska.
Sight-records of foods eaten by box turtles at the Damm Farm
(excluding the many records of individuals foraging in dung or eating
mulberries) were for grasshoppers, caterpillars, and various kinds of
carrion. Box turtles were often seen eating grasshoppers on roads in
early morning; Sophia Damm told me of frequently seeing individuals
catching grasshoppers in her garden. Ralph J. Donahue told me that on
his farm in Bates County, Missouri, an individual of _T. ornata_ made
a circuit of the lawn each morning in summer and ate all the cicadas
(_Magicicada septendecim_) found.
Vertebrate remains found in the stomachs of box turtles seem to result
chiefly from the ingestion of carrion. One box turtle ate a white egg
(unidentified) that had fallen from a nest and another was seen with a
blue down feather clinging to its mouth. Several colleagues have told
me of box turtles eating small mammals caught in snap-traps and Marr
(1944:489) reported a similar incident. J. Knox Jones told me he once
found an ornate box turtle in the nest of a blue-winged teal in Cherry
County, Nebraska; the three eggs in the nest had been broken. The only
authentic record of an ornate box turtle preying on a vertebrate under
natural conditions was one supplied by Ralph J. Donahue who saw an
adult catch and eat one of a brood of bobwhite quail. In many areas
where box turtles are abundant, it is the opinion of local residents
that the turtles decimate populations of upland game birds by eating
the eggs and young of these birds; these opinions result probably from
rare encounters such as the one described by Donahue. I believe that
box turtles at the Damm Farm were sometimes able to catch young frogs
and tadpoles (chiefly _Rana catesbeiana_ and _R. pipiens_) at the
margins of ponds. In autumn literally thousands of young _Rana_ were
present in these places.
Ornate box turtles ordinarily attempt to catch and, without further
examination, to eat, small objects moving on the ground, but are more
critical of stationary objects. Captive turtles, for example, would
immediately chase and seize a grape that was pulled or rolled slowly
across a floor but a stationary grape was examined and then smelled
before it was eaten. Similar observations were made a number of times
with living and dead insects in the field and in the laboratory. A
turtle discovering an object that is of possible value as food,
approaches it closely, turns the head from side to side (presumably
using the eyes alternately to examine the object), and then, with head
cocked at a slight angle, momentarily presses the nostrils against the
object (Pl. 28, Fig. 4). If acceptable as food, the object is then
swallowed whole or taken into the mouth with a series of bites; large
insects are usually broken into several pieces in the process of being
bitten and swallowed. Larger objects, such as dead vertebrates, are
torn to pieces with the beak and forefeet before they are swallowed.
Hatchlings, when fed for the first time, ignored inanimate foods but
eagerly chased mealworms, catching them usually by the anterior end.
The tendency of the young of certain species of turtles (especially
captives) to be more carnivorous than adults is probably due to the
association of movement with food; recognition of inanimate objects as
food is presumably learned by older individuals.
Mulberries (_Morus rubra_), when they are abundant, constitute all or
an important part of the diet of ornate box turtles. On June 4, 1955,
William R. Brecheisen and I drove along a road in Anderson County,
Kansas, and stopped at each mulberry tree that we saw beside the road;
we found at least one specimen of _T. ornata_ under nearly every tree.
Approximately twenty box turtles were collected in this manner in a
little more than one hour. The heads and necks of most were stained
dark-red from the fruit and, in some, nearly the entire shell was
stained. Dissection of these turtles revealed that their stomachs were
distended to two or three times normal size with mulberries; no other
kinds of food were found in the stomachs. Some of the turtles voided
purplish-black fluid from the cloaca when we handled them; the color
of the fluid presumably resulted from mulberries.
Several turtles were observed through binoculars as they foraged.
Individuals snapped or lunged periodically at objects on the ground
along the route of travel. Upon reaching an area where cow dung was
abundant, a turtle would move directly to a pile of dung and begin
tearing it apart with the forelegs or burrowing into it. Turtles most
often foraged in cow dung that had a superficial, dried crust. The
invertebrate fauna of older dung was probably greater than that of
fresh dung. Adult and larval insects were eaten, along with quantities
of dung, as they were uncovered. Sometimes box turtles chased and
caught larger insects that ran a foot or more away from the pile of
dung; the turtles could cover the distance of one foot with three or
four quick steps. Depressions made by box turtles in cow dung, as well
as drier cow dung that had been more completely dissected, were
regarded as characteristic "sign" of _T. ornata_ at the Damm Farm and
in other areas studied (Pl. 26). Several persons have told me of box
turtles "eating cow dung"; these reports, most of them made by
competent observers, probably result from observations of box turtles
ingesting cow dung incidentally, along with some unseen item of food.
Contents of stomachs were analyzed. Scats and contents of lower
digestive tracts, although obtained in large quantity, were unsuitable
for analysis because of the fragmentary nature of the foods they
contained. Relative amounts of various kinds of foods in stomachs were
estimated; volume was determined by displacement of water or fine
shot.
Twenty-three stomachs of adults were selected at random (except for
the fact that empty stomachs were discarded) from more than a hundred
specimens collected in Douglas County, Kansas, in the period from
June, 1954, to June, 1957; the sample included stomachs obtained in
nearly all the months of the season of activity. Kinds of foods in
stomachs did not differ significantly in regard to the sex of the
turtles or to time of year. The stomach of each of two juveniles
(included in Table 6) contained a greater variety of animal food than
did the stomach of any adult, but no kind of animal was eaten by the
juveniles exclusively.
Each of the 23 stomachs contained animal matter and, in addition, all
but two contained at least some plant material from dung, which
constituted up to 20 per cent of total stomach contents.
Insects were present in each of the 23 stomachs and constituted the
bulk of the animal matter; beetles, caterpillars, and grasshoppers
(ranked in descending order) were the kinds occurring most frequently
and constituting the largest average percentages of total
stomach-contents. Most of the beetles were scarabaeids and carabids;
the bulk of the caterpillars were noctuids and arctiids. Grasshoppers,
with one exception, were of a single species, _Melanoplus
differentialis_. It is noteworthy that two of the kinds of insects
frequently eaten (differential grasshoppers and noctuid caterpillars)
are of economic importance in that they damage crops.
TABLE 6.--Kinds of Animals Found in the Stomachs of 25 _Terrapene o.
ornata_ of Both Sexes (23 adults, 2 juveniles) from Douglas
County, Kansas. Frequency of Occurrence (number of stomachs in
which found) is Given for Each Item Listed.
=======================================+=============================
| FREQUENCY OF OCCURRENCE
|--------+-----------+--------
| Adults | Larvae | Total
---------------------------------------+--------+-----------+--------
Gastropoda | | |
_Helisoma_ sp | 1 | | 1
_Succinia_ sp | 1 | | 1
_Polygyra_ sp | 1 | | 1
_Retinella_ sp | 1 | | 1
---------------------------------------+--------+-----------+--------
Crustacea | | |
_Procambaris gracilis_ | 1 | | 1
_Armadillidium vulgare_ | 4 | | 4
---------------------------------------+--------+-----------+--------
Orthoptera (Locustidae) | | |
Locustinae (_Melanoplus | | |
differentialis_) | 13 | | 13
Oedipodinae | 1 | | 1
| | |
Lepidoptera (unspecified) | | 1 | 1
Arctiidae | | 9 | 9
Noctuidae | | 10 | 10
Pyralidae | | 1 | 1
Sphingidae | | 1 | 1
| | |
Diptera (Sarcophagidae) | | 1 | 1
| | |
Coleoptera (unspecified) | 3 | | 3
Cantharidae | | 1 | 1
Carabidae (unspecified) | 6 | | 6
(_Eumolops colossus_) | 1 | | 1
Cerambycidae (_Prionus fissicornis_) | 1 | | 1
Chrysomelidae | | |
(_Diabotrica 12-punctata_) | 1 | | 1
Curculionidae (_Calendra parvulus_) | 3 | | 3
Lampyridae (_Photinus pyralis_) | 2 | | 2
(_Photuris sp._) | | 1 | 1
Phengodidae | | 1 | 1
Scarabaeidae | 11 | | 11
| | |
Hymenoptera (Formicidae) | 2 | | 2
---------------------------------------+--------+-----------+---------
Phalangida | 1 | | 1
| | |
Araneida (_Epeira_) | 1 | | 1
| | |
Diplopoda | 1 | | 1
---------------------------------------+--------+-----------+---------
Vertebrata (carrion) | | | 4
---------------------------------------+--------+-----------+---------
TABLE 7.--Occurrence of Insects, by Frequency and Volume, in Stomachs
of 23 _Terrapene ornata_ from Douglas County, Kansas. Relative
Volume is Based on Total Amount of Food Material Present, Excluding
Stones and Vegetable Material Contained in Dung.
===================+=========+=============+==============+==========
| Insects | Orthoptera | Lepidoptera |Coleoptera
| (all) | | (larvae) |
-------------------+---------+-------------+--------------+----------
Average | | | |
volumetric | | | |
percentage | 88.6 | 28.7 | 26.9 | 32.5
-------------------+---------+-------------+--------------+----------
Range | | | |
(volumetric | trace | | |
percentage) | to 100 | 0 to 100 | 0 to 100 | 0 to 100
-------------------+---------+-------------+--------------+----------
Frequency of | | | |
occurrence | | | |
(percentage | 100 | 52 | 65 | 74
of total stomachs | | | |
in which found) | | | |
-------------------+---------+-------------+--------------+----------
Snails, sowbugs, and the one individual of crayfish found in stomachs
were kinds that could be expected to occur in moist grassland or in
wooded stream courses. Mulberries were present in one stomach and
fragments of bird's-nest fungi (_Cyathus striatus_) were present in
another. Carrion consisted of remains of mammals and birds; the only
identifiable items were bones of the eastern cottontail (_Sylvilagus
floridanus_) and a chicken. Stones up to seven millimeters in diameter
were found in many stomachs; stones constituted as much as half of
total stomach-contents. Presumably the stones were accidentally
swallowed when food was taken from the ground.
The few adequate reports on dietary habits of _T. carolina_ (Allard,
1935:325-326; Carr, 1952:147, 150, 152, 153; Stickel, 1950:361;
Surface, 1908:175-177) indicate that the species is omnivorous but
that individuals tend to be herbivorous or carnivorous at certain
times. Ornate box turtles resemble _T. carolina_ in being
opportunistic feeders but rely on insects as a staple part of the
diet. In this respect the ornate box turtle seems to differ from all
other kinds of box turtles in the United States and it is probably
unique in its habitual utilization of dung communities as a source of
food.