following Mom

A common sight in lakes and ponds this time of year is a brood of little ducklings paddling very close to their mother.

mallard hen and ducklings

A mallard hen escorts her newly hatched brood across the pond to better foraging habitat.

wood duck hen and brood

Wood duck hatchlings have to paddle fast to keep up with their mom.

Mother Duck’s large body moving around the nest was the first thing the newly hatched ducklings saw, and within a day’s time, they imprinted on her, meaning their brains became wired to follow that object faithfully until they mature to full independence.

wood duck hen and brood

Whatever mom does, the ducklings do. When it’s time to rest after hunting for bugs, the ducklings take a break with their mom.

There is a critical period for this type of “filial imprinting” to occur — usually within 24-48 hours of hatching.  Whatever large, mobile object the hatchling sees, it follows — even if it is a human.  This type of imprinting is of obvious survival value to precocial birds, those that are mobile immediately after hatching, as they learn survival skills and are protected by at least one parent.

Konrad Lorenz and imprinted geese

Konrad Lorenz, an early 20th century behavioral biologist, studied imprinting in Greylag Geese by attending to them immediately after hatching.  From then on, they followed him faithfully wherever he went.

You might wonder if imprinting only occurs in birds.  The answer is NO, but there are different types of imprinting, even in birds.  Social and sexual imprinting are key to making sure an individual associates with members of its own species.  Keith Kendrick* cross-fostered sheep and goats immediately after birth (i.e., goats mothered the lambs and sheep mothered the kids), and found that male offspring (but not females) were subsequently irreversibly attracted both socially and sexually to their foster mom’s species more than their own.

animal-imprinting-in sheep and goat (Kendrick, 1995)

Sheep and goat buddies.  From How Stuff Works.

Sort of makes you wonder about Tarzan being raised by apes…

*Kendrick et al. 1995. Mothers determine sexual preferences.  Nature 395: 229-230.