Jackson ratio

Researched and devised by Dr. Oliphant Jackson, the Jackson ratio is a method of determining whether a member of the tortoise species Testudo graeca or Testudo hermanni is maintaining its optimum bodyweight, which is necessary for a successful hibernation.^[1]

Calculation

The Jackson ratio is calculated by taking the weight of the tortoise in grams and dividing it by the cube of the length of the tortoise's carapace in centimeters.^[1] This is essentially a value of the density of the tortoise in g/cm³. The optimal value for this ratio is 0.21 with a range of 0.18–0.22 being acceptable for hibernation. Values significantly less than this indicate an underweight tortoise and larger values are indicative of overweight tortoises.

The Jackson ratio is expressed as a graph of minimum and optimum weights for a given carapace length. This exhibits the same principle without the maths.

References

^ ^a ^b "Jackson Ratio for Tortoises". Tortoise Protection Group. Retrieved 2017-02-24.

ULf Edqvist. "Tortoise Trust Web - The Jackson Ratio Graph - Inappropriate Use". Tortoisetrust.org. Retrieved 2017-02-24.
A. C. Highfield. "Tortoise Trust Web - How to Measure your Tortoise". Tortoisetrust.org. Retrieved 2017-02-24.
"Heosemys grandis forum - Jackson ratio". Heosemys.org. Retrieved 2017-02-24.

Turtle terminology

Carapace
Chelonitoxism
Fibropapillomatosis
Gular scute
Jackson ratio
Plastron
Pyramiding
Shell
Tortoiseshell

Tortoise family

Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Subclass: Anapsida
Order: Testudines
Suborder: Cryptodira
Superfamily: Testudinoidea
Family: Testudinidae

Genera

Species of the tortoise family

Agrionemys

Russian tortoise

Chaco tortoise
Red-footed tortoise
Yellow-footed tortoise
†Chelonoidis alburyorum
†Chelonoidis cubensis
†Chelonoidis lutzae
†Chelonoidis monensis
†Chelonoidis sellovii
†Chelonoidis sombrerensis

Galápagos tortoise

Chelonoidis complex

†Cheirogaster

†Cheirogaster bacharidisi
†Cheirogaster gymnesica
†Cheirogaster schafferi

Chersina

Angulate tortoise

†Hadrianus

†Hadrianus corsoni
†Hadrianus majusculus
†Hadrianus octonaria
†Hadrianus robustus
†Hadrianus schucherti
†Hadrianus utahensis
†Hadrianus vialovi

†Hesperotestudo

†Hesperotestudo percrassa

Pancake tortoise

Pyxis

Leopard tortoise

†Stylemys

†Stylemys botti
†Stylemys calaverensis
†Stylemys canetotiana
†Stylemys capax
†Stylemys conspecta
†Stylemys copei
†Stylemys emiliae
†Stylemys frizaciana
†Stylemys karakolensis
†Stylemys nebrascensis
†Stylemys neglectus
†Stylemys oregonensis
†Stylemys pygmea
†Stylemys uintensis
†Stylemys undabuna

Testudo

Phylogenetic arrangement of turtles based on turtles of the world 2017 update: Annotated checklist and atlas of taxonomy, synonymy, distribution, and conservation status. Key: †=extinct.

Testudines

Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Clade: Diapsida
Order: Testudines

Suborder

Superfamily

Family

Genus

Cryptodira

Chelonioidea
(Sea turtles)

Cheloniidae	†Allopleuron Caretta †Carolinochelys Chelonia †Eochelone Eretmochelys †Gigantatypus †Glarichelys †Itilochelys Lepidochelys †Mexichelys †Miocaretta Natator †Pacifichelys †Syllomus †Tasbacka
Dermochelyidae	†Arabemys †Corsochelys †Cosmochelys Dermochelys †Eosphargis †Mesodermochelys †Psephophorus
	†Euclastes †Peritresius †Procolpochelys †Protosphargis †Puppigerus

Kinosternoidea

Dermatemydidae	Dermatemys
Kinosternidae	Claudius †Hoplochelys Kinosternon Staurotypus Sternotherus

Testudinoidea

Emydidae	†Acherontemys Chrysemys Clemmys Deirochelys Emys Actinemys Emydoidea Glyptemys Graptemys Malaclemys Pseudemys Terrapene Trachemys †Wilburemys
Geoemydidae	Batagur †Banhxeochelys Cuora Cyclemys Geoclemys Geoemyda Hardella Heosemys Leucocephalon Malayemys Mauremys Melanochelys Morenia Notochelys Orlitia Pangshura Rhinoclemmys Sacalia Siebenrockiella Vijayachelys
Platysternidae	Platysternon
Testudinidae	Aldabrachelys Astrochelys Centrochelys Chelonoidis Chersina Cylindraspis †Cymatholcus †Floridemys Geochelone Gopherus †Hadrianus †Hesperotestudo Homopus Indotestudo Kinixys Malacochersus Manouria †Megalochelys †Oligopherus Psammobates Pyxis †Solitudo Stigmochelys †Stylemys Testudo

Trionychia

Carettochelyidae	†Allaeochelys †Anosteira Carettochelys
Trionychidae	Amyda Apalone †Axestemys Chitra Cyclanorbis Cycloderma †Drazinderetes Dogania †Gilmoremys †Hutchemys †Khunnuchelys Lissemys Nilssonia Palea †Palaeoamyda Pelochelys Pelodiscus Rafetus Trionyx
	†Basilochelys †Sinaspideretes

Chelydridae	Chelydra †Chelydrops †Chelydropsis †Emarginachelys †Macrocephalochelys Macrochelys †Planiplastron †Protochelydra
†Nanhsiungchelyidae	†Anomalochelys †Basilemys †Jiangxichelys
†Protostegidae	†Alienochelys †Archelon †Atlantochelys †Bouliachelys †Calcarichelys †Cratochelone †Desmatochelys †Iserosaurus †Notochelone †Ocepechelon †Pneumatoarthrus †Protostega †Rhinochelys †Santanachelys †Terlinguachelys
	†Adocus †Argillochelys †Bashuchelys †Ctenochelys †Prionochelys †Toxochelys

Pleurodira

†Araripemydidae	†Araripemys
†Bothremydidae	†Araiochelys †Arenila †Azabbaremys †Bothremys †Cearachelys †Chedighaii †Chupacabrachelys †Eotaphrosphys †Foxemys †Galianemys †Ilatardia †Inaechelys †Itapecuruemys †Jainemys †Kinkonychelys †Kurmademys †Labrostochelys †Nigeremys †Phosphatochelys †Polysternon †Puentemys †Rosasia †Rhothonemys †Sankuchemys †Taphrosphys †Ummulisani †Zolhafah
Chelidae	Acanthochelys Chelodina Chelus Elseya Elusor Emydura Hydromedusa †Lomalatachelys Mesoclemmys Myuchelys Phrynops Platemys †Prochelidella Pseudemydura Rheodytes Rhinemys †Yaminuechelys
Pelomedusidae	Pelomedusa Pelusios
Podocnemididae	†Albertwoodemys †Bauruemys †Brontochelys †Caninemys †Carbonemys †Cerrejonemys †Cordichelys Erymnochelys †Lapparentemys †Latentemys Peltocephalus Podocnemis †Stupendemys
†Sahonachelyidae	†Sahonachelys †Sokatra

	†Caribemys †Caririemys †Tacuarembemys

Phylogenetic arrangement of turtles based on Turtles of the World 2017 Update: Annotated Checklist and Atlas of Taxonomy, Synonymy, Distribution, and Conservation Status. † = extinct.