Rodent Biology & Control

RodentBiology & Control

Examples of Rodents • Gerbils • Mice • Rats • Squirrels • Woodchucks • Porcupines • Beaver • and….

Objective هدف • Relate the biology of rodents to appropriate control measures.

Overview مرور • Chacteristics and Habits • Purpose • Surveillance and Control Techniques

Norway RatRattusnorvegicus • Characteristics: • Large, thick body • Largest, most aggressive • Blunt muzzle; small ears and eyes • Tail is nearly naked; shorter than combined length of head and body • Fur color brown to dark gray with scattered black hairs

Roof RatRattusrattus • Characteristics: • Relatively slender body • Muzzle pointed; ears and eyes large • Tail longer than combined length of head and body; fairly hairy • Fur color black to brownish-gray

House MouseMusmusculus • Characteristics: • Body small • Ears and eyes large • Fur color grayish-brown with light below • Can be distinguished from immature rats by head and feet proportion in relation to body (young rats have large heads and feet)

Reproduction • Rats • Sexually mature at 3 months • Gestation period 21 days; new estrus cycle begins 4-5 days following litter birth • Produce 3-7 litters per year with 5-7 pups per litter • Mice • Sexually mature at 5 weeks • Produce up to 8 litters per year at 5-6 pups each

Rodent Behaviors • They are nocturnal -- active almost exclusively at night. • They stay close to food and water. • If abundant water is not available (or in poor supply), they will not continuously inhabit an area.

Rodent Behaviors • They travel in defined runways. • They are “neophobic” -- don’t like new objects. • They tend to eat in their harborages.

Rodent Behaviors • Climbing – Rodents are among the most agile of all mammals and are capable climbers • Burrowing – this activity is demonstrated by all commensal rodents with the Norway rat being most adept.

Rodent Senses & Abilities • Sensory acuity - hearing, taste and smell, are much more acute than humans. • Rodents have excellent memories and seldom repeat mistakes.

Senses and Abilities • Swimming – all commensal rodents are good swimmers with the Norway rat being the most adept at this activity.

Medical Importance • Native rodents may contribute to disease (ex. plague and Hantavirus) or economic loss (ex. crop damage). • Imported species are far more destructive. • We are most concerned with commensal rodents: those rodents that are closely associated with man and his environment (derived from the Latin word for "companion at meals.”)

Medical Importance • Rodents can attack people, especially when their populations are large or they are hungry • Rodents historically have been a problem on battlefields and will attack wounded and disabled soldiers

Diseases Associated with Rodents • Plague • Tularemia • Leptospirosis • Salmonellosis • Relapsing fever • Leishmaniasis • Korean hemorrhagic fever • Ratbite fever • Hantavirus • Mosquito- and tick-borne encephalitides • Chikungunya, Onyongyong fever, Lassa fever • Crimean-Congo hemorrhagic fever • Murine and scrub typhus • Tickborne typhus, Q fever • Toxoplasmosis • Helminthic disease (trichinosis)

Rodent Attacks • Rats can injure, maim, and kill people!

Economic Significance • Destroy stored grains, and other foods • They will eat almost anything • Destroy other structures by gnawing • Includes electrical wires, hydraulic hoses, wood, and wallboard • Gnawing - rodents gnaw constantly to wear down teeth

Surveillance • Presence of urine and feces... • Rat urine glows under black light • Smudge marks or rubs • Runs or tracks

Surveillance • Gnawing or other physical damage • Burrows, nests, or food caches • Presence of dead rodents in the open. • Presence of live rodents in the day.

Surveillance • Odors and sounds • Visual observation • Pet excitement

Prevention and Control • Sanitation • IPM • Exclusion and rodent proofing

Rodenticides • Acute (Single-Dose) Rodenticides: • Capable of killing in a single dose, although more effective over multiple feedings • Chronic (Multiple-Dose) Rodenticides: • Requires multiple feeding over several days to cause mortality

Other Control Methods • Trapping • Snap traps • Live traps • Sticky traps

Summary • Chacteristics and Habits • Purpose • Surveillance and Control Techniques

Questions? سوالات

Rodent Biology & Control