========+====================================================
| Males
+-------------------------------+--------------------
Age in | Snout-vent length in mm. | Weight in grams
Years +---------+----------+----------+---------+----------
| | Typical | Observed | | Observed
| Average | range | range | Average | range
--------+---------+----------+----------+---------+----------
1+ | 539 | 432-609 | | |
2- | 615 | 500-676 | 560-674 | 68.2 | 51-92
2+ | 668 | 610-700 | 620-710 | 107.4 | 63-134
3- | 706 | 677-730 | 648-755 | 102.1 | 65-129
3+ | 740 | 701-754 | 667-780 | 147.0 | 93-216
4- | 757 | 731-772 | 725-809 | 139 | 95-251
4+ | 785 | 755-793 | 720-850 | 167.4 | 128-225
5- | 805.5 | 773-810 | 743-855 | 152.4 | 110-198
5+ | 810 | 801-831 | 773-858 | 163.9 | 89-211
6- | 827 | 811-831 | 765-883 | 175.9 | 130-230
7- | 845 | 832-850 | 788-900 | 181.2 | 125-210
8- | 868 | 851-873 | 740-890 | 217.5 | 194-225
8+ | 870 | 861-884 | | |
--------+---------+----------+----------+---------+----------
| Females
+---------+----------+----------+---------+----------
1+ | 581 | | 415-658 | |
2- | 644 | 520-739 | 580-738 | 83.5 | 52-127
2+ | 743 | 685-804 | 670-826 | 135.2 | 73-200
3- | 810 | 740-829 | 730-880 | 149.4 | 98-219
3+ | 836 | 804-869 | 736-915 | 181.2 | 120-268
4- | 866 | 830-880 | 791-920 | 212.3 | 175-243
4+ | 883 | 870-914 | 810-952 | 191.2 | 143-300
5- | 914 | 880-929 | 833-1088 | 209.6 | 136-275
5+ | 932 | 915-954 | 883-990 | 250.4 | 195-336
6- | 965 | 930-961 | 892-1020 | 245.9 | 218-283
6+ | 970 | 955-980 | 885-1003 | 271 | 243-336
7- | 974 | 962-990 | 919-1050 | 251.3 | 150-330
7+ | 1000 | 980-1015 | 930-1085 | 295.6 | 235-375
--------+---------+----------+----------+---------+----------
A racer suddenly startled by close approach of a human usually flees
at high speed. The first part of its course, up to 20 feet or more, is
marked by a violent lateral thrashing of the body and tail, which may
help the snake to gain speed, but which seem chiefly designed to draw
attention of a potential attacker to the spot that the snake is
leaving. In any event, the mode of progression abruptly changes to a
swifter and much smoother travel, and the snake may seem to vanish
completely or as it glides rapidly away, its course may be marked by
the slowly waving tops of tall grass. The trend of travel away from
the site of disturbance is in an irregularly zig-zag course. The
method of crawling, with lateral undulations of the body, supported
against scattered pivot-points along the way, tends to prevent the
snake from moving more than a short distance in a straight line.
In checking traps along hilltop rock ledges in October, I have often
flushed racers that had come to the ledges searching for hibernation
dens. In such an instance the startled racer would usually dart away
down the steep slope at unusually high speed, and within a few seconds
might have covered 100 feet or more, progressing with a minimum of
lateral undulations, and seeming to flow or coast over the ground
surface with scarcely any effort. Although coursing downhill in this
manner provided an effective method of escape, racers startled at the
ledges or on other sloping ground sometimes followed a course parallel
to the ledge, or even turned uphill, with disastrous slowing. Often I
have accomplished capture by hand, by the strategy of running downhill
to get below the escaping snake, causing it to turn back up the slope,
there to be slowed to the extent that it could be overtaken.
A racer that has been flushed, and has disappeared after creating a
commotion by its violent thrashing, may, within a period of minutes,
return surreptitiously to the vicinity, gliding back slowly and
silently from the direction opposite that in which it departed. It may
climb into a tree or bush where, lying stretched on outer twigs and
concealed in dense foliage, it will sometimes permit close approach,
rather than reveal its presence by moving. If too much disturbed
however, such a snake will move away, higher, or to the opposite side
of the clump, with a slow and stealthy gliding motion which is likely
to escape detection. The sudden stops and abrupt changes in direction
make it difficult to follow the course of a climbing racer, even
though it is moving slowly. The tendency to climb to escape danger
seems to be especially strong in the western subspecies, _C. c.
mormon_. In my years of experience with the racers in the chaparral
belt of western Oregon and California, I found that one of the most
characteristic responses to danger was to climb into a bush or low
tree and seek concealment in the thick foliage. In most instances the
snake was from one to eight feet above the ground; usually it did not
attempt to climb high in a tree even when there was opportunity to do
so. The racer's prowess as a climber is limited. In thick brush where
its weight is supported by numerous stiff twigs simultaneously, it is
at home and can travel rapidly, but it cannot cling effectively to
rough bark of a vertical tree trunk as can the rat snakes (_Elaphe_
sp.) and others that are more specialized in their arboreal
adaptations. Chaparral-type shrubs such as _Ceanothus cuneatus_ and
_Arctostaphylos viscida_ were those in which western yellow-bellied
racers were seen climbing most frequently. Crab-apple (_Pyrus
ioensis_) and haw (_Crataegus_ sp.) were the shrubs most frequently
utilized by blue racers on the Reservation. Carr (1950:80) noted that
Florida racers were much less given to tree-climbing than were those
of more northern regions. _C. c. stejnegerianus_ of southern Texas is
reputed to have arboreal tendencies highly developed (Mulaik and
Mulaik, 1942:14).
The racers kept in an outdoor enclosure in the summer of 1962 spent
much of their time above the ground, climbing in several walnut
saplings. Usually in the warmer part of the day three or four of the
five racers in the pen were climbing. In the trees a racer usually lay
extended or in a loose coil among foliage in the outer twigs, at a
height of five to 12 feet. Such a snake might rest for hours in almost
the same position. Racers do not ordinarily enter the water
voluntarily, but they are swift and efficient swimmers when the need
arises. On one occasion a large female, seen near the edge of the pond
on the Reservation, and approached from the landward side, took to the
water without hesitation and swam strongly to the opposite shore more
than 100 feet away. Other observers have recorded similar incidents.
A racer that is suddenly startled at close range may make no attempt
to escape, but instead may coil and perform slow writhing movements,
with the head pressed to the ground and concealed beneath part of the
body. Musk, exuding from the anus is spread over the body surface as
the movements continue. Only a small percentage of the racers found
free in their natural habitats reacted in the manner described. In
each such instance, the circumstances were such that the racer was
prevented from making its usual rapid getaway, either because
temperature was unusually low for activity, or because the snake was
away from suitable cover. After removal from a live-trap, with
handling, and especially clipping of scales, racers were much more
likely to behave in this passively defensive manner, which seemingly
constitutes a second line of defense in snakes which have been
prevented from escaping--either cornered, captured, or injured by a
predator. The musk is creamlike in color and consistency, and is
secreted from sausage-shaped glands in the base of the tail. Its odor
is rather disagreeable, but less so than that of musks of various
other genera. Also, it is less penetrating and lasting than many other
musks. In handling the racers removed from traps I attempted to avoid
being smeared with the musk by grasping the snake by the tail and neck
and keeping its body stretched out. While the snake was being
examined, and measured a droplet of musk would form at the anal
orifice and would begin to flow down the snake's body. To avoid
contact with the musk I would wipe away the droplet with a paper towel
or leaf, but the musk droplet might be replaced several times within
the few minutes that the snake was restrained.
A racer that is confronted with an object arousing its suspicion or
indicating possible danger, may move away slowly with a characteristic
"threat display." The forebody and neck are held rigid, well off the
ground, and slightly arched, with the neck flattened in a vertical
plane--causing this part of the snake to appear from lateral view
larger than it actually is. The tongue is protruded frequently and
waved slowly. A racer that has been disturbed and is trying to gain
shelter in a direction that brings it closer to the danger usually
will adopt this tense attitude, but a single threatening movement will
cause it to abandon its circumspect pose, and panic in an attempt to
reach the nearest shelter in the shortest possible time.
A common response to an alarm is to vibrate the tail. The tail being
long and slender is vibrated much less rapidly than the short,
muscular organ of a rattlesnake, or even the medium-short tail of a
bull snake. The rapid twitching produces a characteristic sound in dry
vegetation. A racer that vibrates its tail is fully active and
aroused; the sound is heard as the snake pauses before it makes a dash
for shelter. At times the sound probably functions as a decoy to
distract the attention of potential predators, affording the racer an
opportunity to escape.
A racer that is cornered or captured usually puts up a spirited
struggle, striking vigorously and repeatedly at its tormentor. If only
cornered, it will make slashing strokes at the enemy, jerking back to
a coil from each stroke in a manner that causes the teeth to lacerate
the enemy's skin in long scratches if the stroke finds its target. The
rapid recoil often causes teeth to be jerked from their sockets and
left embedded in the wound inflicted by the bite. On many occasions in
sustaining a bite from a racer I have received such teeth which have
remained undetected for a day or more until soreness and festering led
to their discovery and removal. A racer that is grasped may deliver
several bites within a few seconds, chewing vigorously to imbed its
teeth to the maximum at each bite.
If grasped by the tail and held clear of the ground, the racer would
swing its body with a rapid whirling and twisting motion, which in a
few seconds would twist off the end of the tail, unless
countermeasures were promptly taken. Many racers, especially the
larger and older ones, have parts of the tail missing, as a result of
such escapes, and perhaps also from freezing in hibernation or from
certain injuries and infections. If grasped by the body, the racer
struggles with a violent lateral thrashing to break the grip of its
captor, at the same time striking to bite and discharging musk,
urinary wastes and feces.
Many of the racers examined bore scars from wounds that were probably
inflicted by predators. A few had survived severe skeletal injuries,
involving deformation of the spinal column or extensive tearing of
muscle and connective tissue layers of the body wall, altering the
normal body shape. A more frequent type of injury involved chiefly the
integument, which had been ripped open by the teeth, claws, or bills
of adversaries, despite the fact that the skin is remarkably tough and
leathery. Patches of scar tissue with scales in irregular sizes,
shapes and patterns characterized such injuries. The most frequently
observed type of injury involved loss of part of the tail. Usually
only a small terminal part was missing, but occasional stub-tailed
individuals had lost as much as three-fourths of the tail.
No consistent trend of difference between the sexes in incidence of
injuries to the tail was noticeable, but there was definite
correlation with age. In the entire sample from the Reservation and
Rockefeller Tract the percentages in each supposed age group (actually
size group) lacking part of the tail were as follows: hatchlings, 2.9
per cent; one-year-olds, 9.5 per cent; two-year-olds, 15.8 per cent;
three-year-olds, 14.3 per cent; four-year-olds, 15.7 per cent;
five-year-olds, 23.2 per cent; six-year-olds, 30.9 per cent;
seven-year-olds, 28.9 per cent; those eight years old or older, 21.1
per cent. The seeming reversal of trend in the older racers is
difficult to explain, but probably results from inadequate numbers in
this part of the sample.
Although the racer's most characteristic response to any disturbance
is to flee at high speed, certain individuals are inclined to behave
aggressively under exceptional circumstances. Records of such
aggressive behavior nearly all pertain to large individuals of the
northeastern black racer (_C. c. constrictor_) in the breeding season.
Cope (1900:794) wrote: "it is courageous and will sometimes attack,
moving forward with the head raised from 1 to 2 feet above the
ground." Ditmars (1944:13) wrote: "Occasional specimens in the
breeding season ... will actually attack ... glide toward an intruder
... striking madly at one's feet or legs." Woods (1944:257) quoted a
13-year-old amateur herpetologist, Leon Gonthier, regarding the
latter's encounter with an aggressive black racer on May 7, 1944, as
follows: "When I ran toward the snake about 20 feet away, it turned
and came for me. As I bent over to catch it, the snake grabbed me by
the shirt and hung on ... held it off with a stick. It jumped twice
more at me and came clear off the ground." Finneran (1948:124)
describing the species' habits in Connecticut, stated: "A farmer ...
constantly warned me away from Coon Ledge during the spring, saying
the snakes were breeding and would 'chase you.' This very thing
happened. In 1943 a blacksnake followed me for approximately ten feet,
and, in 1946, a male aggressively attacked me for a period of three
minutes. There was ample opportunity for escape."
_Natural Enemies_
Little has been published concerning the natural enemies of the common
racer. The king snake (_Lampropeltis getulus_) is notorious for
ophiphagy, and doubtless preys upon the racer at times. Wright and
Bishop (1915:169) wrote of the king snake in Okefinokee Swamp, in
Georgia, that "all the smaller snakes suffer, and of the larger
species, the blacksnake [racer] and spreading adder are the commonest
prey." However, Clark (1949:252) examined 301 stomachs of king snakes
of this species in Louisiana and found no racers, although many other
kinds of snakes were represented, and, collectively, made up the
greater part of the food.
A rat snake (_Elaphe obsoleta_) found in Leon County, Florida, on June
10, 1924, had a racer in its stomach, according to the Patuxent food
habits file of the U. S. Fish and Wildlife Service. A California
garter snake (_Thamnophis elegans terrestris_) was found to have a
juvenal racer in its stomach (Fitch, 1940:96). A large alligator
lizard (_Gerrhonotus multicarinatus_) was found swallowing a small
racer that had been confined with it in a bag (Fitch, 1935:12).
A few records of predation on blue racers by other reptiles on the
Reservation and Rockefeller Tract were obtained. In 25 scats of the
prairie king snake (_Lampropeltis calligaster_), there were 29
vertebrate prey items of which one was a blue racer. On September 15,
1962, an adult male prairie king snake 49-1/2 inches in length was
found to have a 27-inch yearling racer in its stomach. In 254 scats of
the slender glass lizard (_Ophisaurus attenuatus_) vertebrate remains
were rare, but there were scales and bones of one hatchling blue
racer. Among 21 vertebrate prey items in 14 scats of the timber
rattlesnake (_Crotalus horridus_) there were remains of one blue
racer. Among 589 prey items of copperheads there were two juvenal blue
racers (Fitch, 1960:200). In contrast to these scarce records of
racers in the prey of other snakes, there were more frequent records
of the blue racer preying on its own young. The 1008 food items from
479 racer scats contained remains of 16 racers, small young in most
instances.
Raptorial birds are known to be important predators on snakes.
Breckenridge (1944:118) reported finding remains of a blue racer in
the pellet of a marsh hawk (_Circus cyaneus_). Many pellets of the
marsh hawk collected on the Reservation were all found during the
colder half of the year, and they contained no remains of reptiles.
The same seasonal restrictions applied to the many pellets of four
species of owls that were collected, and these also lacked remains of
reptiles. One of the predators whose food habits have been most
thoroughly investigated on the area is the red-tailed hawk (_Buteo
jamaicensis_). Over the period 1955 through 1962, 1131 pellets of
these hawks were collected, many from the Reservation, but more from
localities scattered throughout the eastern one-fourth of Kansas. The
pellets were those of nestlings and fledglings, nearly all collected
from beneath the nests, in late May, June, or early July. Some 49
different nests were represented, and remains of 43 blue racers were
found. In one nest which yielded a total of 191 food items, racer
remains occurred 13 times, but no other nest yielded records of more
than three racers, and some other species of reptiles, notably the
black rat snake (_Elaphe obsoleta_) comprised much more important
components of the food. Since only one meal in 26 contained remains of
racers, it seems that a red-tailed hawk would destroy only a few
racers in the course of a year on its territory of perhaps half a
square mile, and that its predation would not be a major factor in the
racer's ecology.
That the red-tailed hawk is a natural enemy to be reckoned with
throughout the racer's extensive range was demonstrated by the
analysis of contents of 116 stomachs from localities well scattered
over the United States and Canada. Among the 152 vertebrate prey items
represented there were three racers: a juvenile _C. c. constrictor_
from Stag Lake, New Jersey, October 16, 1927; a _C. c. mormon_ from
Weiser, Idaho, April 11, 1930, and a _C. c. stejnegerianus_ from San
Roman, Cameron County, Texas, in the spring of 1938. Because of the
widely scattered geographical origin of these stomachs, a remarkably
large number of species of prey were represented, and no one species
predominated. Small mammals of the genera _Sylvilagus_,
_Spermophilus_, and _Thomomys_ comprised the most important component
of the food; the only other reptile so well represented as the racer
was the common garter snake (_Thamnophis sirtalis_) which likewise had
three occurrences.
In June and July, 1954, a nest of broad-winged hawks (_Buteo
platypterus_) on the Reservation yielded 71 prey items of which seven
were blue racers. At least 19 species of prey were represented,
although specific determinations were not possible in some instances.
The prairie vole with eight records was the most frequent prey, and
the racer and cardinal (nestlings) each had seven, while all other
species were represented by fewer occurrences. Six of the racers were
first-year young but the remaining one was thought to be an undersized
second-year individual. Although an adult racer, especially a large
one, would probably be an adversary too powerful to be killed and
eaten by a broad-winged hawk, this hawk is perhaps one of the more
important natural enemies of the first-year young in the eastern
United States.
Further records of predation on racers by raptors were obtained from
the U. S. Fish and Wildlife Service files through the kindness of Dr.
Wm. H. Stickel. There were three records of such predation by
red-shouldered hawks (_Buteo lineatus_) from Lunenberg, Massachusetts,
May 1, 1896; Portland, Maine, March 16, 1906; and 65 miles northeast
of Sarasota, Florida, June 10, 1918. There were two records of
predation by broad-winged hawks from Catlettsburg, Kentucky, July 26,
1910, and Portland, Connecticut, May 18, 1912. There were four records
of predation by marsh hawks on racers--Peck's Island, Maine, September
18, 1903; Edgartown, Massachusetts, April 12, 1912; West [Tisbury?],
Massachusetts, July 31, 1912; and Okanagan Landing, British Columbia,
June 5, 1918. A sparrow hawk (_Falco sparverius_) from De Ranch,
Wyoming, May 27, 1910, had eaten a racer, as had a barn owl (_Tyto
alba_), from Franklin County, Kansas, November 16, 1922, and a crow
(_Corvus brachyrhynchos_, nestling) from Onaga, Kansas, May 16, 1914.
Perhaps certain mammalian predators are even more important natural
enemies than are raptorial birds, but records of predation on racers
by mammals are few. Substantial samples of scats of opossums and
coyotes from the Reservation have contained no remains of racers. The
Fish and Wildlife Service files include a record of an opossum from
Adrian, Michigan, on April 26, 1934, that had racer remains in its
stomach. No racers were specifically recorded from a collection of 820
scats and 22 stomachs of raccoons (_Procyon lotor_) from Douglas
County, Kansas, reported upon by Stains (1956:43), but occurrences of
unidentified snake may have pertained in part to the racer. Skunks are
probably more important natural enemies, but food habits data from the
Reservation are lacking for the two kinds of skunks occurring there.
Crabb (1941:356) in a study of the food habits of the spotted skunk
(_Spilogale putorius_) in southeastern Iowa, did not report any
reptiles among the many kinds of prey found in scats. Several times in
many years of residence near Medford, Jackson County, Oregon, I saw
remains of racers which appeared to be victims of striped skunks
(_Mephitis mephitis_). Tracks and other sign of the skunks were often
noticed along a little-used road on a hillside, passing between a
pasture and a hay field, with an oak grove, high weeds, and brush,
bordering the road. The racers sometimes found as victims along this
road were small- or medium-sized individuals. In every instance the
predator had begun eating on the tail end of the snake, and later had
abandoned the remains leaving the head and part of the forebody still
intact. Predation had occurred at night. Skunks foraging mostly in
twilight or darkness, probably find racers inactive beneath flat rocks
or in shallow burrows. The skunks would be too slow and clumsy to
catch the snakes in the open when they were fully active.
The funnel traps used for catching the racers also caught many other
kinds of animals. Often a racer and another kind of snake were caught
together, but, ordinarily, in these instances no damage to either
resulted, although racers, copperheads, king snakes, and garter snakes
are all known to eat each other's young. At times, large predatory
ground beetles (_Calosoma scrutator_ and _Pasimachus_ sp.) were
so abundant that a dozen or more were caught together in a trap,
and several times such groups attacked and killed and partly
ate young racers caught in the same traps. White-footed mice
(_Peromyscus leucopus_), deer mice (_P. maniculatus_), harvest
mice (_Reithrodontomys megalotis_), short-tailed shrews (_Blarina
brevicauda_), and least shrews (_Cryptotis parva_) all were caught
rather frequently in the traps, and each, on one or more occasions,
gnawed and killed or severely injured a racer trapped with it. The
attacks probably were motivated by hunger in all instances, the snake
in some instances failing to defend itself or escape because of low
temperature. Occasionally such encounters might occur even under
natural conditions, the mouse or shrew finding and attacking the snake
while the latter was torpid and helpless in its hibernaculum or in a
more superficial temporary shelter.
_Disease_
Relatively few of the racers examined showed signs of disease. The
most common type of affliction was an infection of the skin causing
cankerlike sores, chiefly on the ventral plates, sometimes on the head
or tail. These were seen most often in snakes recently emerged from
hibernation, but persisted later in the season in years of
exceptionally wet weather. Some of the racers most severely afflicted
appeared to be in debilitated condition. The causal organism was not
determined, nor was it definitely determined whether this type of
disease causes mortality.
_Parasites_
The ectoparasites of the racer are chiefly chiggers, the parasitic
larvae of mites. Loomis (1956) in his study of the chigger mites of
Kansas examined many of the racers captured in the early years of my
field work. He checked a total of 130 racers, mostly from the
Reservation, and found four different species of chiggers, all of the
genus _Trombicula_: _T. alfreddugèsi_, _T. lipovskyana_, _T.
kansensis_ and _T. sylvilagi_. The common pest chigger, _T.
alfreddugèsi_, parasitizes most of the species of reptiles, birds, and
mammals occurring in Kansas, and it was by far the most common kind on
the racers. The numbers per racer in different months were as follows:
June, 81; July, 285; August, 432; September, 123; October, 15. Many of
the racers were collected in the relatively cool and moist summers of
1950 and 1951. In a year of typical weather, heaviest infestations
occur in early summer, June or the first half of July, and the numbers
taper off rapidly in the hot but often dry weather of late July,
August, September, and October. In hot, humid weather of early summer
a racer may have several hundred chiggers attached to it, filling most
of the areas of exposed skin between the scales. The chiggers are
conspicuous because of their bright orange color. Like _T.
alfreddugèsi_, _T. lipovskyana_ was also found in large numbers on
racers and is found on many kinds of hosts. Loomis (_op. cit._:1281)
recorded it from one kind of frog, one kind of toad, one kind of
turtle, two of lizards, six of snakes, 19 of birds, and nine of
mammals from eastern Kansas. Five larvae of _T. sylvilagi_ were
recorded from a racer captured in October. That kind of chigger is
primarily a parasite of small mammals, and perhaps cannot develop
successfully when it attaches to a snake. Unlike most other kinds of
chiggers, this species is most in evidence in autumn and winter. A
single larva of _T. kansensis_ was found on a racer in October. This
relatively rare kind of chigger has been found on several kinds of
snakes and small mammals (including pocket gophers) and is known from
hot and dry rocky places. Even the racers that were heavily loaded
with chiggers showed no obvious ill effects, but the chiggers are
potentially vectors of various diseases.
Of the many endoparasites found in racers, the lung fluke, _Neorenifer
lateriporus_ was the only one identified and frequently observed in my
study (Stewart, 1959). This is a digenetic trematode of the subfamily
Reniferinae. The racer is its specific host. The life history is still
unknown, but in other members of the subfamily, all of which
parasitize snakes, an aquatic snail and a frog are required as hosts
at different stages of the life cycle. Presumably _N. lateriporus_ has
similar requirements. The two common local water snails, _Heliosoma
trivolvis_ and _Physa anatina_, are both potential hosts. By far the
most probable frog host is the leopard frog. In wet weather of July
the recently metamorphosed leopard frogs leave the water and disperse
to all habitats, probably carrying with them the parasites acquired in
the tadpole stage. The racers in turn probably acquire their flukes by
eating the young frogs in summer. In any case, the adult racers are
nearly all parasitized, but the flukes have not been found in those
racers that were less than one year old. During their first few
months, the racers are too small to swallow leopard frogs, even the
young. The flukes have been seen in the live racers mostly in May,
when most adults are infested with the flukes. Seemingly at this
season the flukes migrate forward into the mouth of the host.
Probably this is the time when the flukes breed and lay eggs; if so,
the eggs would pass through the digestive tract of the snake and
escape with its feces. The latter are usually left in terrestrial
situations unfavorable for the development of an aquatic stage, but
perhaps some of the eggs are washed into ponds by heavy summer rains.
In late summer and fall the flukes are not to be found in the mouths
of the live snakes.
Most complete records of the flukes present in racers were kept in
1959. The following table shows the numbers of racers examined and the
percentage having flukes in that year.
Ortenburger (1928:182) recorded lung flukes (_Renifer ellipticus_)
from blue racers. In Maryland, McCauley (1945:76) also recorded
numerous lung flukes (_Pseudorenifer_ sp.) in an immature racer 490
millimeters in total length. Parker (1941:34) recorded _Neorenifer
septicus_ from racers collected at Reelfoot Lake, Tennessee,
Greensboro, Georgia, and Kissimmee, Florida; also he recorded _N.
georgianum_ from racers collected at Reelfoot Lake. _N. septicus_ was
recorded by the same author from the water moccasin (_Agkistrodon
piscivorus_) and _N. georgianum_ was also recorded from the king snake
(_Lampropeltis getulus_).
Cloacal smears from the racers examined usually showed an abundance of
ciliate protozoans, either parasites or commensals, and occasionally
nematode worms. Harwood (1933:66) examined two racers from the
vicinity of Houston, Texas, and found four kinds of helminths:
_Kalicephalus agkistrodontis_, _K. rectiphilus_, _Ophidascaris_ sp.,
and _Polydelphis_ sp. Each parasite was found in only one of the two
snakes. McCauley (_loc. cit._) recorded nematodes (_Physaloptera
obtusissima_) from black racers in Maryland, and Ortenburger (_loc.
cit._) recorded _Physaloptera_ sp. from the blue racer.
Table 18. Seasonal Incidence of the Fluke Neorenifer lateriporus,
in Mouths of Blue Racers on the Reservation and Rockefeller Tract
=============+=================+======================
| Number of | Percentage of sample
| racers checked | having flukes
-------------+-----------------+----------------------
Apr. 15-30 | 1 | 100
May 1-15 | 28 | 79
May 15-31 | 25 | 72
June 1-15 | 24 | 50
June 15-30 | 17 | 18
July | 30 | 0
Aug. | 5 | 0
Sept. | 9 | 0
Oct. | 2 | 0
-------------+-----------------+----------------------