Ring-Tailed Ground Squirrels (Notocitellus annulatus): Mexican Mammal Drawn by Jean-Jacques Audubon

by DerdriuMarriner

Squirrels appear to enjoy digging. Tree squirrels descend from treetops to bury nuts. Ground squirrels dig to assure the presence of trees and to design cozy burrows underground.

The word picture of a squirrel generally acknowledges:
•an agile body with a beautifully full tail and impressively reversible ankles;
•an intelligent face with alert ears, big eyes, inquisitive nostrils, and prominent teeth.

Human acquaintances typically adopt one of two attitudes. At one extreme, wildlife-lovers appreciate the athletic mammal’s environmentalism, friendliness, and industriousness. At the other extreme, city and country dwellers articulate intolerance of the attractive rodent’s chewing wood, digging holes, entering attics and garages, and finagling seed from bird feeders.

Contrasting opinions assume their greatest divergence over hole-digging. For environmentalists, squirrel-dug holes contribute to soil aeration and tree regeneration. For farmers and gardeners, the same hollows and mounds endanger crop and plant growth and human perambulation.

Ground squirrels particularly are disdained by cultivators of farms, gardens, and lawns. They excavate holes for caching food and tunnels for living underground. They heave ground into depressions and mounds that rival those of moles and voles in their power to aggravate and infuriate cultivators.

Yet this very behavior inspired amateur naturalist Spencer Fullerton Baird’s (February 3, 1823 - August 19, 1887) interest in a dealer-peddled specimen. The fifteen-year-old Pennsylvanian, subsequently the Smithsonian Institution’s first curator, in 1850, offered the well-preserved carcass to Jean-Jacques Audubon (April 26, 1785 – January 27, 1851). The world’s premier bird observer and painter opined that the ground-dweller originated in the western prairies as the “missing link” between marmots and tree squirrels.

The specimen illustrated by J.J. Audubon "was politely presented to us by Professor Spencer F. Baird, of Carlisle, Pennsylvania, a young Naturalist of eminent attainments." (p. 215)

American naturalist, ornithologist, ichthyologist, and herpetologist Spencer Fullerton Baird (February 3, 1823 - August 19, 1887) became Smithsonian Institution's first curator in 1850.
Spencer Fullerton Baird: 1850 daguerrotype portrait
Spencer Fullerton Baird: 1850 daguerrotype portrait


Jean-Jacques depicted the specimen in his mammalian masterpiece, The Quadrupeds of North America. The publication evidenced the naturalist’s passion for all wildlife -- not just the avian representatives in The Birds of North America. He and his collaborator, Reverend John Bachman (February 4, 1790 – February 24, 1874), found the pelt attractively colored, with a dark body and head and with a tail banding black over a black, buff, and pink background. They found the sciurid intermediately sized between bigger, ground-based marmots and prairie dogs in the Marmotini tribe and:

  • Ground-based “chipping squirrels” – chipmunks -- in the Tamiina subtribe;
  • Tree-based flying and tree squirrels in the respective Pteromyini and Sciurini tribes.

They named it annulated marmot squirrel (Spermophilus annulatus).


c. 1841 oil on canvas portrait of John James Audubon

after painting by John Woodhouse Audubon (November 30, 1812 - February 18 or 21, 1862), son of John James Audubon
after painting by John Woodhouse Audubon (November 30, 1812 - February 18 or 21, 1862), son of John James Audubon


Scientific nomenclature accedes to inquiring minds, scientific breakthroughs, and technological advances. Categories based upon appearance and habitat currently answer to phylogenetic analyses of molecules and morphology. Scientists nowadays appreciate finely differentiated relationships between -- and structures within -- organisms because of sub-cellular investigations. Ground squirrels are among the beneficiaries of research into mitochondria, the cellular sub-units that change specialized chemical energy from food into generalized energy -- adenosine triphosphate (ATP) -- for cells. Analysis of cytochrome b’s role in respiratory complex III’s generating ATP indeed contributes to Mammals Department Curator Kristofer M. Helgen and fellow Smithsonian National Museum of Natural History scientists -- F. Russell Cole, Lauren E. Helgen, and Don E. Wilson -- re-organizing the Spermophilus genus.


Cytochrome b: main subunit of cytochrome bc1 (also known as Complex III), transmembrane protein present in mitochondria of all animals.

Analysis of cytochrome b's role in cellular generalized energy process has been critical to transfer of ring-tailed ground squirrels in Notocitellus genus.
Mitochondrial cytochrome bc1 complex
Mitochondrial cytochrome bc1 complex


Ring-tailed ground squirrels now belong to the genus Notocitellus.  The name combines the Greek adjective noto (“black”) and the Latin noun citellus (“ground squirrel”). The genus divides into two species. Ring-tailed and tropical ground squirrels function as respective common names for the annulatus and adocetus species. Each species gets divided into subspecies. Membership goes according to distribution along western coastal Mexico. Scientists identify ring-tailed ground squirrels as:

  • Notocitellus annulatus annulatus in Manzanillo, state of Colima;
  • N.a. goldmani in Santiago and Tepic, Nayarit.

They indicate tropical ground squirrels in Michoacán as:

  • Notocitellus adocetus adocetus in La Salada, about 40 miles (64.37 kilometers) south of Uruapan;
  • N.a. infernatus in an area 8.5-8.75 miles (13.68-14.08 kilometers) south of El Infiernillo.


All species and subspecies appear grizzled black and tan because of darkly- and palely-flecked fur. The individual hairs are coarse-looking but marmot-like in their softness. The coat becomes brighter during the dry-season breeding months of December through June. The body conveys slenderness while the 15-ringed, tree squirrel-like tail expresses length. The mature head-and-body and tail lengths respectively hover around 11.3 - 18.75 inches (28.7 - 47.6 centimeters) and 5.0 - 9.37 inches (12.7 - 23.8 centimeters). The female -- who is larger-skulled than the male -- imitates marmots in possessing three sets of mammary glands despite all other ground squirrels typically having four to six pairs. One set is at the front limbs’ juncture with the body. Two sets locate at the rear limbs’ union with the posterior.


skull of male ring-tailed ground squirrel: specimen from Manzanillo, State of Colima, Western Mexico region, Mexico's central Pacific coast

Plate 31, opposite p. 245
A.W. Howell (1938)
A.W. Howell (1938)

skull of female ring-tailed ground squirrel: specimen from Manzanillo, State of Colima, Western Mexico region, Mexico's central Pacific coast

Plate 26, opposite p. 240
A.H. Howell (1938)
A.H. Howell (1938)


Small molars and stout incisors aid in digesting:

  • Fronds, especially prickly pear cactus (Opuntia spp);
  • Fruits, especially figs (Ficus spp) and plums (Prunus mexicana);
  • Insects, especially ants, grasshoppers and termites;
  • Nuts and seeds, especially calabash (Crescentia alata) and mesquite (Prosopis spp).

Thumbs at the ends of the front limbs’ long, narrow feet bring food into internal, large cheek pouches directly behind small premolars. Broad auditory bullae and rounded ears catch the slightest sounds from such predators as:

  • Coyotes;
  • Hawks;
  • Snakes.

The omnivorous carnivore counter-attacks by:

  • Balancing on haunches and tail;
  • Chirping warnings and whistling alarms differentiating predatory presences from range breaches;
  • Navigating undergrowth;
  • Scaling trees, with the tail curved tree squirrel-like over the back;
  • Sneaking into burrows.


Burrows are constructed with entrances, hallways, and rooms. The entrances can be built as gently sloping horizontal or straight up-and-down vertical entries. The hallways give corridor access to such rooms as:

  • Chambers, in which mating, playing and sleeping take place;
  • Nests, from which annual litters of four to six newborns are thought to emerge after maternal gestations of about 30 days;  
  • Pantries of stored food, to which residents retire if above-ground supplies are scarce or when the morning or midday sun is too hot.

The rooms have grass-lined ceilings, floors, and walls. They house the changing family of parents and progeny. Males may be short-lived since they disperse soon after weaning at one-to-two months. Females remain in their birth-ranges.


ring-tailed ground squirrel: illustration by Ernest E. Thompson, alias of Ernest Thompson Seton (August 14, 1860 – October 23, 1946), co-founding pioneer of Boy Scouts of America

A.H. Howell, Revision of the North American Ground Squirrels (1938), Plate 9, opp. p. 28
A.H. Howell, Revision of the North American Ground Squirrels (1938), Plate 9, opp. p. 28


In birth- and dispersal-ranges, ringtails build cavities under:

  • Dense vines growing from tropical forest floors up large trees;
  • Fallen leaves in oil palm groves;  
  • Thorn-riddled trunks of catclaw (Senegalis greggii) and mesquite.

In home- and relocation-ranges, tropical ground squirrels burrow under:

  • Drought-tolerant undergrowth on open ground;
  • Rocks along canyon sides and small ravines;
  • Roots of calabash, mesquite and plum trees.

Ringtails and tropicals additionally construct homes along the wildland-urban interface. They dwell in a coastal mini-strip that is attracting farmers and ranchers. They have one of two reactions to the growing agro-industrial presence:

  • Build under the natural hedges and stone walls of cultivated fields or within the corrals of grazing pastures;
  • Retreat to their area’s arid plateaus.


Figure 15 - Distribution of the subspecies of Citellus annulatus: 1=C.a. goldmani; 2=C.a. annulatus

A.H. Howell, Revision of the North American Ground Squirrels (1938), p. 163
A.H. Howell, Revision of the North American Ground Squirrels (1938), p. 163


The two species come face-to-face with agro-industry in the northern part of the southwest Mexican state of Guerrero. Ring-tailed and tropical ground squirrel populations only confront one another in Guerrero. Otherwise, ringtails enjoy predominantly humid environments -- at altitudes from sea level to 3,937 feet (1,200 meters) -- in the lowland plains and tropical deciduous forests of:

  • Colima;
  • Nayarit.

Their smaller counterparts otherwise favor seasonally arid habitats – at elevations from sea level to 9,842.52 feet (3,000 meters) -- in the overgrown mesquite woodlands, tropical deciduous forests, and upland desert shrubs of:

  • Jalisco;
  • Michoacán.

Tropical ground squirrels nevertheless have the survival advantage over their ring-tailed counterparts. Their homeland includes such protected areas as:

  • Infiernillo;
  • Pico Tancitaro National Park.


Laguna La María beguiles visitors with natural beauty and wildlife, including ring-tailed ground squirrels:

located about 6 miles (9.7 km) southwest of Colima's iconic active volcano, Volcán de Fuego
Laguna La María, State of Colima, west central Mexico
Laguna La María, State of Colima, west central Mexico


Thirty-nine (39) years distance scientific knowledge of the first-known peddled specimen of the ring-tailed ground squirrel in 1838 from the second-known in 1877. One-hundred-fifty-eight (158) years divide the depiction of the ring-tail in The Quadrupeds of North America of 1851 and the re-organization of temperate ecozone-dwelling ground squirrels in “Generic Revision in the Holarctic Ground Squirrel Genus Spermophilus” of 2009. The reclusiveness of the sciurid’s behavior and the remoteness of their natural habitats -- within territory just 35 miles (156.33 kilometers) wide by 200 miles (321.87 kilometers) long -- discourage interactions. But the steady expansion of farms, ranches, and vacation homes into the semi-arboreal, semi-terrestrial’s isolated ranges does result in leaps in familiarity unknown to 19th- and 20th-century time-dwellers.


Annulated marmot squirrel (Spermophilus annulatus): synonyms of ring-tailed ground squirrel (Notocitellus annulatus)

Plate LXXIX, No. 16, page 213
Plate LXXIX, No. 16, page 213

Conclusion: Friendly, inquisitive burrowers in human interface


Squirrels amaze humankind with their acrobatics, aesthetics, and amiability. Does a bad fur day or photo opportunity ever cross a squirrel’s path? As with their specifically arboreal or strictly terrestrial counterparts, ring-tailed and tropical ground squirrels enchant with their upbeat reactions to range invasions. They enjoy:

  • Bread;
  • Lettuce;
  • Meat;
  • Tortillas.

They entertain locals with agile feats and friendly inquisitiveness. They keep insect pests out of barns and outbuildings. But they keep on:

  • Burrowing, to combat claw overgrowth;
  • Chewing, to halt teeth overgrowth;
  • Devouring field corn and sorghum, garden beans, and orchard fruits, to maintain healthy diets.

Domestication and protection promise these obligate seed-dispersers sustainability. Domesticators and scientists nevertheless will need flashlights when night-strolling through ground squirrel-burrowed grounds!


Colima's iconic palm groves are favorite habitats for ring-tailed ground squirrels.

en el palmar: palm grove, Colima, Mexico
en el palmar: palm grove, Colima, Mexico



My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.


Reverend John Bachman: co-explorer of North America's quadrupeds, including ring-tailed ground squirrels, with Jean-Jacques Audubon

C.L. Bachman, John Bachman The Pastor of St. John's Lutheran Church Charleston (1888), frontispiece.
C.L. Bachman, John Bachman The Pastor of St. John's Lutheran Church Charleston (1888), frontispiece.

Sources Consulted


Álvarez-Castañeda S.T.; Castro-Arellano I.; Lacher, T.; Vázquez, E. (2008). Spermophilus annulatus. In: IUCN 2008. IUCN Red List of Threatened Species. Retrieved on January 31, 2014. 

  • Available at: http://www.iucnredlist.org/details/20479/0

Audubon J.J.; Bachman J. (1842). "Spermophilus annulatus." Journal of the Academy of Natural Sciences of Philadelphia 8:319.

Audubon J.J.; Bachman J. (1851). The Quadrupeds of North America. Vol. II. New York: V.G. Audubon, MDCCCLI. Retrieved on January 31, 2014.

  • Available via Internet Archive at: https://archive.org/details/quadrupedsofnort02audu

Bachman, Catherine L. John Bachman, The Pastor of St. John's Lutheran Church, Charleston. Charleston, SC: Walker, Evans & Cogswell,1888.

  • Available via Biodiversity Heritage Library at: http://biodiversitylibrary.org/page/23769090

Bisby F.A.; Roskov Y.R.; Orrell T.M.; Nicolson D.; Paglinawan L.E.; Bailly N.; Kirk P.M.; Bourgoin T.; Baillargeon G.; Ouvrard D. (red.) (2011). Species 2000 & ITIS Catalogue of Life: 2011 Annual Checklist. Species 2000: Reading, UK. Retrieved on January 31, 2014. 

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de Grammont P.C.; Cuarón, A. (2008). "Spermophilus adocetus." In: IUCN 2008. IUCN Red List of Threatened Species. Version 3.1. Retrieved on January 31, 2014. 

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Helgen K.M.; Cole F.R.; Helgen L.E.; and Wilson D.E (2009). "Generic Revision in the Holarctic Ground Squirrel Genus Spermophilus." Journal of Mammalogy 90(2):270–305

Herron M.D.; Castoe T.A.; Parkinson C.L. (2004). "Sciurid Phylogeny and the Paraphyly of Holarctic Ground Squirrels (Spermophilus)." Molecular Phylogenetics and Evolution 31(3):1015-1030. 

Howell, Arthur H. Revision of the North American Ground Squirrels with a Classification of the North American Sciuridae. North American Fauna No. 56. Washington DC: U.S.D.A. Bureau of Biological Survey, April 1938.

  • Available via Biodiversity Heritage Library at: http://biodiversitylibrary.org/page/25806412

Merriam C.H. (1903). Proceedings of the Biological Society of Washington 16:79. 

Mott S. "Spermophilus annulatus: ring-tailed ground squirrel (On-line)." Animal Diversity Web. University of Michigan Museum of Zoology. Retrieved on January 31, 2014. 

  • Available at: http://animaldiversity.ummz.umich.edu/accounts/Spermophilus_annulatus/

Murie J.; Michener G. (1984). The Biology of Ground-Dwelling Squirrels. University of Nebraska Press. 

"Notocitellus adocetus: Tropical Ground Squirrel." Smithsonian National Museum of Natural History: North American Mammals. Retrieved on January 31, 2014. 

  • Available at: http://www.mnh.si.edu/mna/image_info.cfm?species_id=732

"Notocitellus adocetus adocetus (Merriam, 1903)." ITIS Report. Integrated Taxonomic Information System. Retrieved on January 31, 2014. 

  • Available at: http://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=931031

"Notocitellus annulatus: Ring-tailed Ground Squirrel." Smithsonian National Museum of Natural History: North American Mammals. Retrieved on January 31, 2014. 

  • Available at: http://www.mnh.si.edu/mna/image_info.cfm?species_id=733

"Notocitellus annulatus annulatus (Audubon and Bachman, 1842)." ITIS Report. Integrated Taxonomic Information System. Retrieved on January 31, 2014. 

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Nowak R. (1991). Walker's Mammals of the World. Johns Hopkins University Press.

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San Blas: port municipality on Pacific coast of State of Nayarit, native habitat of ring-tailed ground squirrels

panorama of San Blas
panorama of San Blas
the end which is also the beginning
the end which is also the beginning

Ring-tailed ground squirrel in March at La Bajada, Nayarit, Mexico: photo by Jim Zipp

10x14 Photo Puzzle with 252 pieces. Packed in black cardboard box, 5 5/8 x 7 5/8 x 1 1/5. Puzzle image 5x7 affixed to box top
Photo Jigsaw Puzzle of Ring-tailed Ground Squirrel from Ardea Wildl...

Smiling Squirrel on Bike: black t-shirt

caption: "Smile ... It's good for the environment."
Smiling Squirrel on Bike
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Me and my purrfectly purrfect Maine coon kittycat, Augusta "Gusty" Sunshine

Gusty and I thank you for reading this article and hope that our product selection interests you; Gusty Gus receives favorite treats from my commissions.
DerdriuMarriner, All Rights Reserved
DerdriuMarriner, All Rights Reserved
Updated: 10/19/2021, DerdriuMarriner
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DerdriuMarriner on 01/29/2014

Kathleen Duffy, Squirrels are fun to watch. It's wonderful that the grey squirrels are living a "great life" in your area. They can't help digging up bulbs, though, and I love coming across their hidden nut treasures when I re-landscape the garden and yard.
Your interactions with squirrels, now and back then, are charming. It always feels like a special accomplishment, a winsome level of rapport, for wildlife to eat out of our hands. It such a statement of trust.

KathleenDuffy on 01/29/2014

What a fascinating article! I love watching the squirrels in the communal garden where I live. Even though they dig up the bulbs when planting their nuts. They are grey squirrels. They have a great life as our garden is an oasis of calm in the busy city. They overtook the red squirrels which, I believe, are now mainly found in the north. When I lived in Canada we used to have our breakfast by the window and the red urban squirrels would feed out of our hands. thank you for such a detailed article.

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