Rodents Continued: Rats Dr. N. Matthew Ellinwood, D.V.M., Ph.D. February 22, 2012 I OWA S TATE U NIVERSITY C OLLEGE OF A GRICULTURE AND L IFE S CIENCES

Taxonomy Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Rodentia Superfamily: Muroidea Family: Muridae Subfamily: Murinae Genus: Rattus Species: norvegicus (brown rat)

Non-domestic “Brown Rat” Rattus desiginates “true” rats or old world rats Rattus norvegicus (city rat, sewer rat – also the black rat Rattus rattus): a domesticated opportunist Other species of rats may act as opportunists in cities but are usually competitively replaced by the brown or black rat

Rats in Popular Culture Important figures in Indian and Chinese mythology In western culture, almost uniformly a negative image Perhaps associated with the Black Death –Yersinia Pestis –30-60% of Europe's inhabitance – –Mongols catapulting infected corpses –Caffa, Crimea in 1347 –Genoese traders took the plague to Sicily

Origins Originated in China Spread to Europe New world in 1700s Now world wide

Natural History Life span: up to 3 years (extreme cases to 2- 5 yr) Sexual maturity: days Estrous; 4-5 days Gestation is 21 days Weaning; 3-4 weeks Pups; 6-12 per litter Tolerate group housing better than mice –Males assist with/tolerate nursing young

Housing Ease of housing/cleaning critical Rodent chow, less than 6 months since milling Slotted cage top feeder Drip bottle water –Draining/drowning Bedding changes –More frequent than mice 30-70% Humidity o F

Feeding Rodent Chow Coprophagic

Anatomy Rats lack a gall bladder Harderian gland –Pigmented tears – Porphyrin staining

Communication Ultrasonic vocalization –Young Elicits and directs maternal search behavior Diminishes after 14 days old, especially around males –Adult Response to predators or danger frequency and duration of vary by sex/repro status Females during mating Chirping: short, high frequency, and ultrasonic –socially induced “laughing” at play, mating, and when tickled Bruxing, or teeth-grinding –Triggered by well being and 'self-comforting' during stress –Clicking or 'burring' sound

Fancy Variants Rat and Mouse Club of America American Fancy Rat and Mouse Association Sendai virus and rat mortality

Origin of Rat Fancy and Research Rat baiting Popular in Britain –Cruelty to Animals Act 1835 –70 gambling rat pits Suppliers began breeding and supplying as pets Color variants started Show placement in 1901

Variants Siamese rat

Hooded Rat

American Blue

Laboratory Common Laboratory Rat Strains –Wistar rat: Albino white Wistar Institute, Henry Donaldson, 1906, first rat biomed strain –Sprague Dawley rat: outcrossed albino, WI, 1925 –Long-Evans rat Wistar and wild cross – outbred, behavior and obesity –Zucker rat Lois M. and Theodore F. Zucker, obesity reseasrchers Resecessive pbesity trait (leptin receptor polymorphism)

Knockouts Knockout rats exist but are far less common

Diseases Mammary tumors Obesity Ulcers over salivary gland Malocculusions Chronic respiratory disease –Multifactorial (m. pulmonis) Bacterial pneumonia –S pneumoniae Red eye

GUINEA PIG MANAGEMENT Cavia porcellus

Origin Cavia porcellus – domesticated Cavia aperia – wild wild – Peru, Argentina, Brazil, Uruguay also known as Cavies domesticated 16 th century – England

Varieties of Guinea Pigs Traditional  American or English – short hair  Abyssinian – whorls of short rough hair  Peruvian – long hair

Varieties of Guinea Pigs New varieties  Silky – medium length soft hair  Teddy – short, coarse hair  American Crested – short hair with contrasting whorl on forehead  Rex – very short, soft hair  Hairless

Traditional varieties of guinea pigs

American – short hair

Abyssinian – whorls of short hair

Peruvian – long hair

New varieties of guinea pigs

Silky – soft, medium hair

Teddy – short, coarse hair

American crested – contrasting whorl on head

Rex – very short, soft hair

Hairless – (well, almost)

Basic Guinea Pig compact stocky body tailless diurnal – actually  short naps night and day sebaceous marking glands - rump open rooted teeth 

Additional characteristics vocalize – at least 11 sounds good swimmers seldom jump rarely intentionally bite or scratch need frequent handling lifespan – 5 yr average, ~8 yr max.

Uses of Guinea Pigs Pets Scientific research Food

Home Sweet Home Temperature: 70, 65 – 79 Space  < 350 gm 60 sq. in.  > 350 gm 101 sq. in.  max size 1.2 x 3.8 cm mesh or solid

Home Sweet Home Bedding  wood shavings – not cedar, pine  shredded paper  not dusty  timothy hay overlay optional  clean weekly

Home Sweet Home Humidity 50%; 40 – 70 Light cycle 12:12 Air changes 10 – 15 per hour

Digestive System Strict herbivores Hind gut fermenters – cecum  Lactobacilli sp.  primary fatty acid – propionic acid

NUTRITION require vitamin C have higher folic acid requirement sensitive to excess Ca, Vit. A, Vit. D  leads to metastatic calcification  mineralization of soft tissues

Feeding Additional Requirements  ~ 6 gm feed/100 gm body weight  % protein  % crude fiber Use guinea pig feed!!! NOT RABBIT FEED  no vit. C and high in vit. D

Feeding Management Messy feeders Use J-feeders not bowl

Water Management Glass/clear bottles preferred Like to play with waterers  will empty water bottle and/or  stop up the opening  check frequently Change & Clean water bottle daily Automatic waterers  check daily; acidify water at source  reduces pseudomonas

Water Management Glass/clear bottles preferred Like to play with waterers  will empty water bottle and/or  stop up the opening  check frequently Change & Clean water bottle daily Automatic waterers  check daily; acidify water at source  reduces pseudomonas

REPRODUCTION age to sexual maturity estrous cycle days gestation days

SEXING male: straight slit female: Y-shaped

SEXING male: straight slit

SEXING female: Y-shaped

BREEDING females pair at 400gm; 2-3 months males pair at 600 gm; 3-4 months breed females before 6 months  otherwise pubic symphysis fuses  must relax at parturition  Response to the hormone relaxin  Guinea pig once used in bioassays for relaxin

Care of Young precocial – born  furred, eyes open, teeth erupted  walking within 2 hours two nipples – inguinal region  can care for four young  litters 3-4 (range 1-6)

Care of Young milk  3.9% fat  8.1% protein  3.0% lactose

DISEASES genetic infectious environmental nutritional others

DISEASES malocclusion – over growth of teeth causes  environmental \inadequate opportunity wear down teeth  genetic \teeth do not meet properly in guinea pigs  lower premolars may be tilted inward  eventually tongue is trapped

INFECTIOUS DISEASES Bordetella bronchiseptica - pneumonia  do not house with subclinical carriers  rabbits, cats, dogs other infectious diseases are much less common

OTHER DISEASES vitamin C deficiency – scurvy metastatic calcification  mineralization of soft tissues heat stroke  85º F+, high humidity, lack of ventilation barbering  small bald patches

Public Health Risks minimal diseases guinea pigs may carry  Bordetella, Salmonella, Yersinia pseudotuberculosis, Streptococcus

CHINCHILLA MANAGEMENT Chinchilla lanigera

Origin Two species in the wild –Chinchilla brevicaudata Shorter, stockier, and facing extinction A previously extant species is already extict –Chinchilla lanigera Chinchilla lanigera – domesticated wild – Peru, Argentina, Bolivia, Chile Spanish discovered them in 16 th century

Crespuscular –Active – require wheels Names after the Chincha people of the Andes: “Little Chincha” Hunting in the 19 th century –Fur trade led to rarity in the wild Rock crevices in the wild Can jump up to 6 feet high

In the wild, groups called herds Nonseasonally polyestrous Gestation is 111 days –Usually two offsping –Precocial Prey species defense –Fur release –Urine spraying

Dust baths –Fine volcanic dust (pumice) Diet –Pelleted chinchilla with timothy hay Raisin supplement 1-2 per day Do not over supplement on fruits and vegetables

Research Importance Hearing –Range and anatomy Chagas disease –Parasitic diseae causing American trypanosomiasis Gastrointestinal disease Listeriosis

Colors of Chinchilla

Standard Grey

Ebony

Homozygous beige

Heterozygous beige

Brown Velvet

Black velvet

Golden mosaic

Sapphire

Silver

Silver white

Albino white

Pure white

Degus South American rodent Related to Guinea pigs Smaller, social rodents