A PMP EDUCATIONAL UPDATE  |   JUNE 2021  |  View online
DTY Rodent Management
Know your foes

By Dr. Stuart Mitchell

As cryptic critters, mice and rats possess physiological and anatomical talents to challenge even the savviest pest management professionals (PMPs). To know your foes, and get control, requires a deep understanding of biology, behavior — and now, technology.

From the Latin rodere, meaning “to gnaw,” rodents make up the Order Rodentia. Nearly 40 percent of all mammal species are rodents. Mammals possess pelage (hair or fur) and mammary glands.

Mice and rats gain environmental perspective and perceive things quite well. Such perception comes from encountering heat, odors, structural guidelines, shadows, corners, holes and more. They also figure out things by gnawing, and encountering and/or releasing sebum (oil from glands), urine and pointed-end scats. Other factors to consider:
  • Autolysis, or the "fresh" stage, begins immediately after the rodent dies, as gut bacteria digest cells and tissues.
  • Their vision isn’t great. Mice possess visual acuity of about 20/2000 and rats about 20/600. In human terms, with a visual acuity of 20/600, one could see at 20 feet what someone with 20/20 vision could see at 600 feet. Legal blindness is defined as 20/200 or worse. Human visual acuity is 40 to 60 times sharper than a rat. As a result, mice and rats can’t detect motion until about 33 feet away. To compensate, mice and rats rely upon kinesthetic (awareness of position and bodily movements via sensory organs in the muscles and joints) and thigmotactic (touch) navigation.
  • Their hearing is great. Through directional pinnae (external ears) and hearing acuity of about 100 kHz (100,000 cycles per second), mice and rats perceive and communicate in the ultrasonic range. By comparison, human hearing acuity is about 20 kHz (20,000 cycles per second).
  • They are toe runners. With foot pads and vestigial thumbs, mice and rats are digitigrade, which means they walk and run on their toes without their heels touching the ground and with their soles elevated. Mice walk at about 0.29 feet per second, or fps (0.19 mph), and run at about 12 fps (8 mph). Rats walk at about 0.65 fps (0.44 mph), and run at about 12 fps (8 mph). Movement can determine gender, maturation, body size, fitness, and behavioral characteristics.
  • Urine is a big deal in their world. Torricelli’s Law states the rate of flow increases with the height of the vessel. The short lengths and small diameters of mice and rats’ urethras, coupled with viscosities and surface tensions, fragment their urine into droplets. This allows mice and rats quicker elimination and continuous travel. It reduces vulnerability to predators, increases territorial marking, and facilitates urinary communication. Urine possesses information regarding individuals, gender, colonies and reproduction.
Industry manufacturers continue to strive to “build a better mouse trap” for PMPs to outwit rodents and keep them out of structures. Among the latest technologies are smart traps with built-in sensor technology, which allow you to place snap traps within remote structural areas. Water and weather-proof smart traps powered by reliable, fully integrated batteries assure 24/7/365 monitoring. Working in tandem with a smartphone app, you receive time-stamped reports on the presence and capture of mice and rats. You work smarter, not harder — avoiding laborious trap checking, which saves precious, reallocatable time.

Now that you know your foes a little better, get control using ferocious trapping power!

Stuart Mitchell, DO, DVM, PsyD, BCE, is an entomologist, veterinarian, observing physician and consulting clinical psychologist, and a regular contributor to Pest Management Professional's Direct to You series.

PMP's Direct To You provides pest management professionals with educational refreshers on timely and critical topics essential to operational success. Look for the content-rich PMP Direct To You archives at mypmp.net/direct-to-you-archive.

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