Animal Diversity Web

Ge­o­graphic Range

Tome's spiny rats range from Cen­tral Amer­ica in Nicaragua, Costa Rica and Panama to the Pa­cific low­lands of South Amer­ica in Ecuador and Colom­bia. (Moo­jen, 1948; Pat­ton, 1987; Reid, 2009)

• Biogeographic Regions
• neotropical
  • native

Habi­tat

Tome's spiny rats pri­mary in­habit low­land trop­i­cal ever­green for­est up to 800m in el­e­va­tion. They are found in forests rang­ing from dry to very wet, and in­habit both pri­mary and sec­ondary growth, but have a pref­er­ence for sec­ondary growth. They tend to in­habit areas with for­est gaps, shorter canopies, and higher den­si­ties of smaller trees, logs and woody vines, but are over­all quite gen­er­al­ized and non-spe­cific in their use of avail­able mi­cro­hab­i­tat. (Adler, 1996; Adler, 2000; Lam­bert and Adler, 2000; Reid, 2009; Tomblin and Adler, 1998)

• Habitat Regions
• tropical

• Terrestrial Biomes
• forest
• rainforest

• Range elevation

  0 to 800 m

  0.00 to 2624.67 ft

Phys­i­cal De­scrip­tion

Tome’s spiny rats have stiff fur and nar­row flex­i­ble spines. Their upper pelage is glossy and chest­nut-brown to grey-brown, and their un­der­parts are usu­ally white. Tome's spiny rats have long nar­row heads and pointed snouts, naked dark-col­ored ears, large brown eyes, and very long whiskers. They have bi­col­ored tails, with grey tops and white bot­toms. Their tails are not longer than their bod­ies; a defin­ing char­ac­ter­is­tic of genus Proechimys is that their tails that are less than 90% of the length of the rat's head and body. The tails of Tome's spiny rats break off fre­quently, so adult rats may be found with­out tails (around 8-25% of adults are tail­less). Their hind feet are long and nar­row with black soles and white tops. Young Tome's spiny rats are typ­i­cally grey-brown with white un­der­parts. Mor­pho­log­i­cal mea­sure­ments vary greatly among pop­u­la­tions of Tome's spiny rats. Most adults av­er­age 300-400 grams, but older in­di­vid­u­als have been mea­sured at over 700 grams. Ad­di­tion­ally, Tome's spiny rats change in mass through­out the sea­sons as well; rats have larger body mass in the wet sea­son, when re­sources are abun­dant, and have lower mass in the dry sea­son, when re­sources are lim­ited. Most adults are be­tween 180-270 mil­lime­ters long. Ear length ranges from about 23-26 mm, hind foot length ranges from 50-60mm, and tail length ranges from about 160 to 180 mm. The den­tal for­mula of Tome's spiny rats is I 1/1, C 0/0, P 1/1, M 3/3. The skull of the Tome's spiny rat is elon­gate, has dis­tinct, well de­vel­oped supra­or­bital and pari­etal ridges, large bul­lae, and a long, nar­row in­ci­sive fora­men. The mo­lars of Tome's spiny rats have four coun­ter­folds in M3 and M2, three to four coun­ter­folds in M1, lower pre­mo­lars with four and lower mo­lars with three coun­ter­folds. Skull length ranges from 58-67 mm and skull width ranges from 28-31 mm. Size and mor­phol­ogy does not dif­fer sig­nif­i­cantly be­tween the sexes. (Ben­shoof, et al., 1984; Em­mons and Feer, 1990; Gli­wicz, 1983; Gli­wicz, 1984; Kel­log, 1946; McKee and Adler, 2002; Moo­jen, 1948; Pat­ton, 1987; Thomas, 1911)

• Other Physical Features
• endothermic
• bilateral symmetry

• Sexual Dimorphism
• sexes alike

• Range mass

  200 to 700 g

  7.05 to 24.67 oz

• Average mass

  300-400 g

  oz

• Range length

  180 to 275 mm

  7.09 to 10.83 in

• Average length

  230 mm

  9.06 in

Re­pro­duc­tion

Tome's spiny rats have a promis­cu­ous mat­ing sys­tem, im­plied by their widely over­lap­ping home ranges, lack of ter­ri­to­ri­al­ity, and larger home ranges of sex­u­ally ac­tive males. There is no ev­i­dence of mate de­fense or ter­ri­to­r­ial be­hav­ior in this species. Tome's spiny rats may be fac­ul­ta­tively monog­a­mous at low pop­u­la­tion den­si­ties. (En­dries and Adler, 2005; Gli­wicz, 1984; Sea­mon and Adler, 1999)

• Mating System
• polygynandrous (promiscuous)

Tone's spiny rats re­pro­duce through­out the year, and may re­pro­duce sev­eral times a year. How­ever, re­pro­duc­tion is timed such that most preg­nan­cies line up with the pe­riod of low­est food sup­ply (late in the dry sea­son, which gen­er­ally spans from No­vem­ber-April), and most young are born at the pe­riod of peak food sup­ply (the be­gin­ning of the rainy sea­son, in May-Oc­to­ber). This pat­tern re­flects the need for rich and abun­dant food dur­ing lac­ta­tion, which is the most en­er­get­i­cally costly pe­riod for fe­male ro­dents. The length of re­pro­duc­tion pe­riod can vary greatly be­tween pop­u­la­tions and re­gions, from four to 11 months long. The ges­ta­tion pe­riod for Tome's spiny rats is typ­i­cally about 60 days long. They birth 2-4 off­spring per lit­ter, and the av­er­age birth weight of new­born rats is 30 grams. (Adler and Beatty, 1997; Adler, 1995; Adler, 1998; Adler, 2000; Gli­wicz, 1984; Sea­mon and Adler, 1999)

• Key Reproductive Features
• year-round breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual
• viviparous

• Breeding interval

  Breed several times per year; more frequent during rainy season

• Breeding season

  4-11 months

• Range number of offspring

  2 to 4

• Average gestation period

  60 days

Parental in­vest­ment by Tome's spiny rats is not well stud­ied. After a short ges­ta­tion pe­riod of 60 days, fe­males nur­ture their young through lac­ta­tion. Young Tome's spiny rats are likely nested in bur­rows until they are weaned from their moth­ers. Young are born at the time of peak food sup­ply, al­low­ing fe­males to meet the en­er­get­i­cally costly de­mands of lac­ta­tion and en­sur­ing that there will be food avail­able for young once they have been weaned. (Adler and Beatty, 1997; Em­mons and Feer, 1990; Gli­wicz, 1984)

• Parental Investment
• precocial
• pre-independence
  • provisioning
    • female

Lifes­pan/Longevity

The me­dian life ex­pectancy of Tome's spiny rats is 6.5-10 months of age, with max­i­mum lifes­pan rang­ing from 36 to 53 months. The life ex­pectancy of the Tome's spiny rat is very right-skewed, with most in­di­vid­u­als hav­ing short lifes­pans just past the age of first re­pro­duc­tion, with few sur­viv­ing past 2 years of age. Max­i­mum known lifes­pans for Tome's spiny rats are 4.4 years in the wild, and 5 years in cap­tiv­ity. (Jones, 1982; Oaks, et al., 2008)

• Range lifespan
  Status: wild

  4.4 (high) years

• Range lifespan
  Status: captivity

  5 (high) years

• Typical lifespan
  Status: wild

  6.5 to 10 months

Be­hav­ior

Tome's spiny rats are fos­so­r­ial and noc­tur­nal. They in­habit sub­ter­re­nean bur­rows, which are nor­mally dug near to water in areas with sparse veg­e­ta­tive cover. Many rats in­habit bur­rows at the bases of palm trees, one of their main food sources. They rest in these bur­rows through­out the day, and come out to for­age at night. Bur­rows may be in­hab­ited by a sin­gle ro­dent, or may be co-oc­cu­pied by mul­ti­ple males and fe­males. Co-oc­cu­pancy of bur­rows is rel­a­tively com­mon, and there is no ev­i­dence of ter­ri­to­r­ial be­hav­ior in this species.

Pop­u­la­tion sizes and dy­nam­ics of Tome's spiny rats are highly vari­able. In gen­eral, is­land pop­u­la­tions have much higher den­si­ties, more sta­ble pop­u­la­tions, larger in­di­vid­u­als and lower re­pro­duc­tive rates com­pared to main­land pop­u­la­tions. Den­si­ties, re­pro­duc­tive rates and sur­vivor­ship can vary greatly be­tween dif­fer­ent is­land pop­u­la­tions and main­land pop­u­la­tions. Den­si­ties on is­land pop­u­la­tions can range from 12 in­di­vid­u­als per hectare up to 50 in­di­vid­u­als per hectare. Main­land pop­u­la­tions are much more dis­persed, with an av­er­age of 6 in­di­vid­u­als per hectare. Pop­u­la­tion den­si­ties also fluc­tu­ate on a sea­sonal basis, with den­si­ties being high­est in the wet sea­son and low­est in the dry sea­son. Main­land pop­u­la­tions fol­low a pat­tern with dis­tinct phases in pop­u­la­tion den­sity: num­bers de­crease in the dry sea­son, in­crease dur­ing the first half of the rainy sea­son when re­sources are abun­dant, and de­crease in the sec­ond half of the rainy sea­son.

Tome's spiny rats over­lap in range with Ho­plomys gym­nu­rus, the ar­mored rat, and both species ex­ploit the same food re­sources and ex­pe­ri­ence the same sea­sonal lim­i­ta­tions. The species are likely able to per­sist sym­patri­cally be­cause they have dif­fer­ent mi­cro­hab­i­tat pref­er­ences; the ar­mored rat is found mainly in undis­turbed forests along streams with wet, rocky mi­cro­hab­i­tats, whereas Tome's spiny rats are dis­trib­uted gen­er­ally through­out the habi­tat with no spe­cific mi­cro­hab­i­tat pref­er­ence. Ad­di­tion­ally, Tome's spiny rats ex­hibit dom­i­nant be­hav­ior over ar­mored rats. Lev­els of ag­gres­sion in Tome's spiny rats in­crease dur­ing the dry sea­son, when re­sources are more scarce. (Adler, 1995; Adler, 1996; Adler, 2000; Dupre, et al., 2015; En­dries and Adler, 2005; Flem­ing, 1971; Gli­wicz, 1984; McKee and Adler, 2002; Sea­mon and Adler, 1999; Shar­gal, et al., 1999; Tomblin and Adler, 1998)

• Key Behaviors
• fossorial
• nocturnal
• motile

Home Range

Tome's spiny rats gen­er­ally have very large home ranges which over­lap ex­ten­sively with one an­other; total range over­lap varies from 300 to 5700 square me­ters, and core home range over­lap varies from zero to 180 square me­ters. Total home range sizes vary from 180 to 2375 square me­ters, with core ranges vary­ing from 40 to 470 square me­ters. Av­er­age home range sizes are larger in the rainy sea­son (av­er­age of 1260 square me­ters) than the dry sea­son (av­er­age of 740 square me­ters), and there is greater range over­lap in the rainy sea­son. The home ranges of males are mar­gin­ally larger than those of fe­males. (En­dries and Adler, 2005; Sea­mon and Adler, 1999)

Com­mu­ni­ca­tion and Per­cep­tion

Com­mu­ni­ca­tion and per­cep­tion in Tome's spiny rats is not well un­der­stood. These rats have large eyes which are likely im­por­tant for see­ing at night, as they are noc­tur­nal. A re­lated species, Tri­no­mys yone­na­gae, uses chem­i­cal sig­nalling via anal glands for recog­ni­tion of in­di­vid­u­als, so scent recog­ni­tion may be used in spiny rats as well. (Em­mons and Feer, 1990; Manaf, et al., 2003; Pat­ton, 1987)

• Perception Channels
• visual
• tactile
• chemical

Food Habits

Tome's spiny rats are pri­mar­ily fru­giv­o­rous, and fruit abun­dance is the main fac­tor in de­ter­min­ing their pop­u­la­tion den­sity. Tome's spiny rats con­sume a very broad array of fruits and seeds; in a cap­tive study, they con­sumed vir­tu­ally all of the 97 species of for­est fruits of­fered to them. They have a pref­er­ence for con­sum­ing fruits with larger seeds, in­clud­ing plants in the palm fam­ily (f. Are­caceae) such as black palm (As­tro­caryum stan­d­leyanum) and wine palm (At­talea bu­tyracea). They are also known to con­sume the fruits of the large-seeded tree species Dipteryx oleifera. They may also scat­ter­hoard their seeds. Tome's spiny rats are not pri­mar­ily seed-eaters, as they leave be­hind vi­able seeds from most of the fruit they eat. Al­though fruits are the most im­por­tant part of the diet of Tome's spiny rats, they are also my­cophagous. They are known to con­sis­tently con­sume ar­bus­cu­lar my­c­or­rhizal fungi, but their pop­u­la­tion den­si­ties are less de­pen­dent on this food source. Fungi are likely to be more im­por­tant in sup­ple­ment­ing the ro­dents’ diets when fruit and seeds are more scarce, or may have im­por­tance in pro­vid­ing es­sen­tial nu­tri­ents not found in fruit and seeds. (Adler and Beatty, 1997; Adler, 1995; Car­va­jal and Adler, 2008; Dit­tel, et al., 2015; Man­gan and Adler, 1999)

• Primary Diet
• herbivore
  • frugivore
  • granivore
• mycophage

• Plant Foods
• seeds, grains, and nuts
• fruit

• Other Foods
• fungus

• Foraging Behavior
• stores or caches food

Pre­da­tion

The role of Tome's spiny rat as a prey species is not well un­der­stood, but they are likely an im­por­tant prey species to neotrop­i­cal for­est preda­tors as they are the most abun­dant neotrop­i­cal ro­dent. The com­mon op­pos­sum (Didel­phis mar­su­pi­alis) is a known preda­tor of Tome's spiny rats, and other po­ten­tial preda­tors in­clude the gray four-eyed op­pos­sum (Phi­lan­der opos­sum), the brown four-eyed opos­sum (Metachirus nudi­cau­da­tus), the white-nosed coati (Nasua nar­ica), the spec­ta­cled owl (Pul­satrix per­spic­il­lata) the mot­tled owl (Strix vir­gata), and sev­eral large snakes in­clud­ing the species Boa con­stric­tor, Both­rops asper, Mastigodryas melanolo­mus, and Spi­lotes pul­la­tus.

Tome's spiny rats have spines that are adapted from their guard hairs, which likely act as preda­tor de­fense. Tome's spiny rats ex­hibit tail au­ton­omy, which is a very unique trait among ro­dents. Au­ton­omy of ap­pendages is quite com­mon in many in­ver­te­brate groups as an an­tipreda­tor de­fense, but true au­ton­omy is ex­ceed­ingly rare in mam­mals, pre­sent in ap­prox­i­mately 30 species of ro­dents across eight fam­i­lies. Mam­mals can­not re­gen­er­ate their tails, so they may func­tion only once as an an­tipreda­tor de­fense. Rates of tail loss in pop­u­la­tions of rats vary be­tween 8% to up to 25%. Rates of tail loss are lower on smaller is­lands; as tail loss is hy­poth­e­sized to be an anti-pre­da­tion mech­a­nism, lower rates may be a re­sult of fewer preda­tors on smaller is­lands. (Adler, 1996; McKee and Adler, 2002; Pat­ton, 1987; Shar­gal, et al., 1999)

• Known Predators

  • Common oppossum, Didelphis marsupialis
  • Gray four-eyed oppossum, Philander opossum
  • Brown four-eyed opossum, Metachirus nudicaudatus
  • White-nosed coati, Nasua narica
  • Spectacled owl, Pulsatrix perspicillata
  • Mottled owl, Strix virgata
  • Boa constrictor, Boa constrictor
  • Fer-de-lance, Bothrops asper
  • Mastigodryas melanolomus
  • Spilotes pullatus

Ecosys­tem Roles

Tome's spiny rats are often the most abun­dant ro­dent in low­land trop­i­cal forests, and are thought to be the most wide­spread ro­dent through­out much of Cen­tral Amer­ica and north­west­ern South Amer­ica. These rats serve as im­por­tant dis­persers of trop­i­cal plant seeds due to their broad fru­giv­o­rous diet and their scat­ter­hoard­ing ten­den­cies. Ad­di­tion­ally, Tome's spiny rats are not pri­mar­ily seed eaters; the ma­jor­ity of large seeds re­moved by the rats are not ac­tu­ally con­sumed and are still vi­able after the rats dis­pose of them. Tome's spiny rats dis­perse seeds an av­er­age of five me­ters from where they are col­lected, but many seeds are also de­posited more than 10 me­ters from where they are col­lected. Due to their pref­er­ence for fruits with larger seeds, Tome's spiny rats may be par­tic­u­larly im­por­tant for the dis­per­sal of large-seeded species that other ro­dents are not ca­pa­ble of eat­ing, such as the fruits of black palm (As­tro­caryum stan­d­leyanum). Seed re­moval rates are higher among is­land pop­u­la­tions than main­land pop­u­la­tions due to the higher pop­u­la­tion den­si­ties on is­lands. Tome's spiny rats may also have a role in the dis­per­sal of ar­bus­cu­lar my­c­or­rhizal fun­gal spores which are nec­es­sary for the growth of many trop­i­cal plants, as these spores are found in 77% of Tome's spiny rat feces. The Tome's spiny rat’s pref­er­ence for as­so­ci­a­tion with treefall gaps and young for­est in­di­cate it may be a very im­por­tant species for the re­gen­er­a­tion of trees in dis­turbed area via dis­per­sal of my­c­or­rhizal fungi and seeds. Tome's spiny rats are used as hosts by the lar­vae of bot­flies (Cutere­bra). Preva­lence is quite low, av­er­ag­ing around 5%, but vary­ing by pop­u­la­tion (be­tween 2-8%). Bot­fly preva­lence is not de­pen­dent on rat pop­u­la­tion den­sity, and preva­lence in Tome's spiny rats is high­est in the dry sea­son. Tome's spiny rats are also a reser­voir host for the par­a­sitic try­panosome Leish­ma­nia, al­though they are only weakly in­fec­tive to sand flies, the in­ter­me­di­ate hosts of Leish­ma­nia, so they may not be an im­por­tant reser­voir for this par­a­site. How­ever, be­cause they are often the most abun­dant low­land for­est ro­dent in their range, they may be a very im­por­tant reser­voir on a pop­u­la­tion or re­gion-wide scale. Tome's spiny rats may also be a reser­voir host for Try­panosoma cruzi. Tome's spiny rats have also been found in­fected as an in­ter­me­di­ate host with the tape­worm species Echinococ­cus oli­garthrus. (Adler, 1995; Adler, et al., 2003; Car­va­jal and Adler, 2008; D'Alessan­dro, et al., 1981; Dit­tel, et al., 2015; Hoch and Adler, 1997; Lam­bert and Adler, 2000; Man­gan and Adler, 1999; Travi, et al., 1994; Travi, et al., 2002)

• Ecosystem Impact
• disperses seeds

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

The meat of Tome's spiny rats is com­monly con­sumed by rural Afro-Colom­bian com­mu­ni­ties; ro­dents are trapped lo­cally but the meat is not fre­quently sold in mar­kets. Tome's spiny rat meat is a good source of pro­tein and is not as­so­ci­ated with the trans­mis­sion of any dis­eases. Ad­di­tion­ally, due to their con­sump­tion of seeds and my­c­or­rhizal fungi, as well as their pref­er­ence for mi­cro­hab­i­tats with treefall gaps and younger for­est, Tome's spiny rats may have an im­por­tant role in the re­gen­er­a­tion of dis­turbed for­est through seed and fungi dis­per­sal. This species also serves as an im­por­tant model species of trop­i­cal ro­dent for stud­ies on ro­dent re­pro­duc­tion, pop­u­la­tion dy­nam­ics and seed dis­per­sal. (Adler and Beatty, 1997; Adler, 1995; Adler, 1996; As­prilla-Perea, et al., 2012; Man­gan and Adler, 1999)

• Positive Impacts
• food
• research and education

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

Tome's spiny rats are a reser­voir of cu­ta­neous leish­ma­ni­a­sis, and can be found nat­u­rally in­fected with mul­ti­ple species of Leish­ma­nia. Tome's spiny rats car­ry­ing Leish­ma­nia are only weakly in­fec­tive to sand flies, the in­ter­me­di­ate hosts of Leish­ma­nia; how­ever, be­cause they are often the most abun­dant low­land for­est ro­dent in their range, they may be a very im­por­tant reser­voir on a pop­u­la­tion or re­gion-wide scale. Tome's spiny rats may also be reser­voirs of Try­panosoma cruzi, the causative agent of Cha­gas Dis­ease in hu­mans. (Travi, et al., 1994; Travi, et al., 2002)

• Negative Impacts
• injures humans
  • carries human disease

Con­ser­va­tion Sta­tus

• IUCN Red List

  Least Concern

• US Federal List

  No special status

• CITES

  No special status

• State of Michigan List

  No special status

Con­trib­u­tors

Laura Eliuk (au­thor), Uni­ver­sity of Man­i­toba, Jane Wa­ter­man (ed­i­tor), Uni­ver­sity of Man­i­toba, Tanya Dewey (ed­i­tor), Uni­ver­sity of Michi­gan-Ann Arbor.

Ref­er­ences

Adler, G. 1995. Fruit and seed ex­ploita­tion by Cen­tral Amer­i­can Spiny Rats, Proechimys semi­spinosus. Stud­ies on Neotrop­i­cal Fauna and En­vi­ron­ment, 30: 237-244.

Adler, G. 1998. Im­pacts of re­source abun­dance on pop­u­la­tions of a trop­i­cal for­est ro­dent. Ecol­ogy, 79: 242-254.

Adler, G. 2000. Trop­i­cal tree di­ver­sity, for­est struc­ture and the de­mog­ra­phy of a fru­giv­o­rous ro­dent, the spiny rat (Proechimys semi­spinosus). Jour­nal of Zo­ol­ogy Lon­don, 250: 57-74.

Adler, G., S. Davis, A. Car­va­jal. 2003. Bots (Diptera: Oestri­dae) in­fest­ing a neotrop­i­cal for­est ro­dent, Proechimys semi­spinosus(Ro­den­tia: Echimyi­dae), in Panama. The Jour­nal of Par­a­sitol­ogy, 89: 693-697.

Adler, G., T. Lam­bert. 1997. Eco­log­i­cal cor­re­lates of trap re­sponse of a neotrop­i­cal for­est ro­dent, Proechimys semi­spinosus. Jour­nal of Trop­i­cal Ecol­ogy, 13: 59-68.

Adler, G. 1996. The is­land syn­drome in iso­lated pop­u­la­tions of a trop­i­cal for­est ro­dent.. Oe­colo­gia, 108: 694-700.

Adler, G., R. Beatty. 1997. Chang­ing re­pro­duc­tive rates in a Neotrop­i­cal for­est ro­dent, Proechimys semi­spinosus. Jour­nal of An­i­mal Ecol­ogy, 66: 472-480.

As­prilla-Perea, J., Y. Mos­quera-Mar­tinez, A. Moreno-Lopez. 2012. Proechimys semi­spinosus (spiny rats): a na­tive species with promis­ing po­ten­tial for Afro-Colom­bian com­mu­ni­ties in the Chocó De­part­ment, Colom­bia. Cal­da­sia, 34: 385-396.

Ben­shoof, L., T. Yates, J. Froehlich. 1984. Note­wor­thy records of mam­mals from east­ern Hon­duras. South­west­ern Nat­u­ral­ist, 29: 511-514.

Car­va­jal, A., G. Adler. 2008. Seed dis­per­sal and pre­da­tion by Proechimys semi­spinosus and Sci­u­rus granaten­sis in gaps and un­der­storey in cen­tral Panama. Jour­nal of Trop­i­cal Ecol­ogy, 24: 485-492.

D'Alessan­dro, R., R. Rausch, G. Morales, S. Col­let, D. Angel. 1981. Echinococ­cus in­fec­tions in Colom­bian an­i­mals. The Amer­i­can Jour­nal of Trop­i­cal Med­i­cine and Hy­giene, 30: 1263-1276.

Dit­tel, J., T. Lam­bert, G. Adler. 2015. Seed dis­per­sal by ro­dents in a low­land for­est in cen­tral Panama. Jour­nal of Trop­i­cal Ecol­ogy, 31: 403-412.

Dupre, S., T. Lam­bert, G. Adler, L. Hegde, E. Kennedy. 2015. Ag­gres­sive and in­ves­tiga­tive be­hav­iors of two sym­patric species of echimyid ro­dents, Proechimys semi­spinosus and Ho­plomys gym­nu­rus, in Cen­tral Panama.. Ethol­ogy Ecol­ogy & Evo­lu­tion, 29: 1-8. Ac­cessed De­cem­ber 01, 2016 at http://​dx.​doi.​org/​10.​1080/​03949370.​2015.​1078414.

Em­mons, L., F. Feer. 1990. Neotrop­i­cal rain­for­est mam­mals: a field guide. Chicago, IL, USA: Uni­ver­sity of Chicago Press.

En­dries, M., G. Adler. 2005. Spac­ing pat­terns of a trop­i­cal for­est ro­dent, the spiny rat (Proechimys semi­spinosus), in Panama. Jour­nal of Zo­ol­ogy Lon­don, 265: 147-155.

Flem­ing, T. 1971. Pop­u­la­tion ecol­ogy of three species of Neotrop­i­cal ro­dents.. Mis­cel­la­neous pub­li­ca­tions / Uni­ver­sity of Michi­gan, Mu­seum of Zo­ol­ogy, 143: 1-77.

Gli­wicz, J. 1983. Age in­di­ca­tors in the spiny rat Proechimys semi­spsi­nosus. Trop­i­cal Ecol­ogy, 24: 299-304.

Gli­wicz, J. 1984. Pop­u­la­tion dy­nam­ics of the spiny rat Proechimys semi­spinosus on Or­chid Is­land (Panama). Biotrop­ica, 16: 73-78.

Hoch, G., G. Adler. 1997. Re­moval of black palm (As­tro­caryum stan­d­leyanum) seeds by spiny rats (Proechimys semi­spinosus). Jour­nal of Trop­i­cal Ecol­ogy, 13: 51-58.

Jones, M. 1982. Longevity of cap­tive mam­mals. Zo­ol­o­gis­cher Garten Neue Folge Jena, 52: 113-128.

Kel­log, R. 1946. Three new mam­mals from the Pearl Is­lands, Panama.. Pro­ceed­ings of the Bi­o­log­i­cal So­ci­ety of Wash­ing­ton, 59: 57-62.

Lam­bert, T., G. Adler. 2000. . Mi­cro­hab­i­tat use by a trop­i­cal for­est ro­dent, Proechimys semi­spinosus, in Cen­tral Panama. Jour­nal of Mam­mol­ogy, 81: 70-76.

Manaf, P., L. de Brito-Gi­ti­rana, E. Oliveira. 2003. Ev­i­dence of chem­i­cal com­mu­ni­ca­tion in the spiny rat Tri­no­mys yone­na­gae (Echimyi­dae): anal scent gland and so­cial in­ter­ac­tions. Cana­dian Jour­nal of Zo­ol­ogy, 81: 1138-1143.

Man­gan, S., G. Adler. 1999. Con­sump­tion of ar­bus­cu­lar my­c­or­rhizal fungi by Spiny Rats (Proechimys semi­spinosus) in eight iso­lated pop­u­la­tions. Jour­nal of Trop­i­cal Ecol­ogy, 15: 779-790.

McKee, R., G. Adler. 2002. Tail au­ton­omy in the Cen­tral Amer­i­can spiny rat, Proechimys semi­spinosus. Stud­ies on Neotrop­i­cal Fauna and En­vi­ron­ment, 37: 181-185.

Moo­jen, J. 1948. Spe­ci­a­tion in the Brazil­ian Spiny Rats (Genus Proechimys, Fam­ily Echimyi­dae). Lawrence, Kansas: Uni­ver­sity of Kansas Pub­li­ca­tions. Ac­cessed De­cem­ber 17, 2017 at http://​gutenberg.​polytechnic.​edu.​na/​4/​2/​7/​2/​42720/​42720-h/​42720-h.​htm#​Page_​342.

Oaks, J., J. Daul, G. Adler. 2008. Life span of a trop­i­cal for­est ro­dent, Proechimys semi­spinosus. Jour­nal of Mam­mol­ogy, 89: 904-908.

Pat­ton, J. 1987. Species groups of spiny rats, genus Proechimys (Ro­den­tia: Echimyi­dae). Pp. 305-345 in B Pat­ter­son, R Timm, eds. Stud­ies in neotrop­i­cal mam­mal­ogy: es­says in honor of Philip Her­shkovitz. Chicago, IL, USA: Chicago Field Mu­seum of Nat­ural His­tory.

Reid, F. 2009. A field guide to the mam­mals of Cen­tral Amer­ica and South­east Mex­ico. New York, USA: Ox­ford Uni­ver­sity Press.

Sea­mon, J., G. Adler. 1999. Short-term use of space by a neotrop­i­cal for­est ro­dent, Proechimys semi­spinosus. Jour­nal of Mam­mol­ogy, 80: 899-904.

Shar­gal, E., L. Rath-Wolf­son, N. Kro­n­feld, N. Dayan. 1999. Eco­log­i­cal and his­to­log­i­cal as­pects of tail loss in spiny mice (Ro­den­tia: Muri­dae, Acomys), with a re­view of its oc­cur­rence in ro­dents. Jour­nal of Zo­ol­ogy, 249: 187-193.

Thomas, O. 1911. New ro­dents from S. Amer­ica. An­nals and Mag­a­zine of Nat­ural His­tory, 8: 250-256.

Tomblin, D., G. Adler. 1998. Dif­fer­ences in habi­tat use be­tween two mor­pho­log­i­cally sim­i­lar trop­i­cal for­est ro­dents. Jour­nal of Mam­mol­ogy, 79: 953-961.

Travi, B., L. Arteaga, A. Léon, G. Adler. 2002. Sus­cep­ti­bil­ity of Spiny Rats (Proechimys semi­spinosus) to Leish­ma­nia (Vian­nia) pana­men­sis and Leish­ma­nia (Leish­ma­nia) cha­gasi. Memórias do In­sti­tuto Os­waldo Cruz, 97: 887-892.

Travi, B., C. Jaramillo, J. Mon­toya, I. Se­gura, A. Goncalves, A. Zea, I. Vélez. 1994. Didel­phis mar­su­pi­alis, an im­por­tant reser­voir of Try­panosoma (Schizotry­panum) cruzi and Leish­ma­nia (Leish­ma­nia) cha­gasi in Colom­bia. The Amer­i­can Jour­nal of Trop­i­cal Med­i­cine and Hy­giene, 50: 557-565.