The Definitive "Are Beavers Born With The Innate Disposition To Build Dams, Or Do They Learn It From Older Beavers?" Thread

In the discussion of prolepsis, I - for one - regularly throw around the supposed "example" that beavers are born with the innate disposition to build dams, and that this is not "learned" after birth from their parents. The assertion would imply that while this behavior may be amplified from watching others after birth, it is not primarily dependent on observation after birth, and that baby beavers separated from older beavers at birth would still build dams.

Pretty obviously the truth or falsity of this assertion bears on the issue of exactly what kind of behaviors are transmitted genetically over generations, and plays into the whole "blank slate" controversy. If beavers are born with certain types of behaviors being innate, then it's not much of a leap to consider that humans are too.

There are probably lots of other significant examples, but Beavers really stand out as dramatic examples which capture the imagination. It therefore probably makes good sense to focus on them as a litmus test example - if beavers can be established to have this disposition programmed into them before any personal exposure of any kind to prior dam-building, then I would think most all the other alleged examples of genetic dispositions in the natural world will be correspondingly easy to accept - or harder to accept if innate beaver dam-building is a myth.

We've discussed this in the forum on the past, primarily in the thread I will link below. Some links were produced, primarily by Don if I recall correctly, but i don't recall that we found any kind of "gold standard" article from a respected publication or source that really nailed down the question with persuasiveness. And I also know that some people dispute the contention that beavers are "born" with this behavior programmed in them, and they consider the assertion to be totally false.

Thus this thread is born. Every time we discuss anticipations/prolepsis we come around eventually to dealing with this question of what in fact we are able to observe in nature as to whether "patterned" behavior is totally learned after birth, or is partially encoded in our genetics. The title of this thread will hopefully make it more findable on the future when we need these sources. So as time goes by, I would appreciate it if those of us who are interested in this question could use this thread to collect the best links which bear on it, positively or negatively. If this is true, let's embrace it, if it's false, let's blow it out of the water.

Post

RE: Is There A Relationship Between "Anticipations" and "Instinct"?

(Since I am suggesting we always ought to be planning our seminar presentations)

[…]

On the symbolism of pigs/hogs I think there is some material which help explain the reference. We surely know it it existed from the Boscoreale cup and the Horace reference. I think there is a church father comment also referencing it in which hogs are cited as pursuing pleasure singlemindedly.

Numerous animals would work for the others but any that are known for their instinctive behavior, beavers and their…

Cassius

April 23, 2021 at 5:23 AM

Don's previous suggested threads:

https://home.uchicago.edu/~rjr6/articles/Instinct--Encyclopedia%20of%20Animal%20Behavior.pdf

Animal Instincts: Not What You Think They Are

Marc Bekoff explains how many different animal species show grief, friendship, gratitude, wonder, and a range of other emotions.

greatergood.berkeley.edu

The Sound of Running Water Puts Beavers in the Mood to Build

This one weird trick can help you exploit a beaver's natural instincts.

www.mentalfloss.com

Note also: The article on "the sound of running water puts beavers in the mood to build" might also be an example of how outside influences trigger resulting behaviors, as seems to be a part of the "image" theory.

The University of Chicago article ends as written below, and its overall tone and content appears to me to reinforce the position of something like: "Beavers *are* born with innate dispositions to build dams, but the more exposure they have to their groups while growing up the better they build."

At this moment I would say that of the three cites above, the University of Chicago article appears most persuasive, while the other two articles are more "fluffy." However even the University of Chicago article is more of a "history of science" approach than a "this is what was found in laboratory tests under controlled conditions" approach. It would be highly desirable to find instances of the latter.

The Contemporary Resolution:

Three basic positions have been taken on animal instinct. From Descartes through the early work of Lorenz, instincts were understood to be constituted by chains of reflexes that respond to certain environmental releasers. James Watson, B. F. Skinner, Z. Y. Kuo, and other behaviorists in the first part of the twentieth century rather attempted to account for apparently fixed patterns of behavior by appeals to subtle modes of conditioning. The later Lorenz and evolutionary biologists like Ernst Mayr (1904–2005) established the third and most recent conception of instinct, one that recognized the role of genetically determined, species-specific information as well as the environmental conditions required for the implementation of the information. Mayr epitomized this recognition in his proposal that two kinds of programs governed animal behavior, a more closed program and a more open program (Mayr 1974). Closed programs were those in which the releasing mechanisms were controlled by the genome of the species, such as mate recognition and display in many animals. For instance, fertile female Drosophila of one species, if reared in isolation and placed among males of several species that displayed to her, would unerringly receive only the male of her own species. However, freshly hatched graylag goose chicks would follow any object of the right size, if exposed to the moving object (e.g., Lorenz’s head while swimming) during a critical period in the young gosling’s life. The chicks rapidly learned the stimulus that released the fixed behavior of following. In some species of bird, a chick raised with chicks of a different species would imprint on the foster species and attempt to mate with its members. These cases of imprinting represent a more open program. The mechanisms of instinct, therefore, differ depending on the species of animal and the relative open or closed character of the program. Most behavior biologists today recognize these different instances of instinctual modes of behavior and have thus revitalized the instinct concept.

Springer International Publishing AG, part of Springer Nature 2018, Jennifer Vonk and Todd Shackelford
Encyclopedia of Animal Cognition and Behavior
10.1007/978-3-319-47829-6_1064-1

Instinct
Robert J. Richards
Departments of History, Philosophy, and Psychology, The University of Chicago, Chicago, IL, USA

I see references to someone named Lars Wilson studying this, but the references look questionable:

Running water is sound of spring for beavers | Juneau Empire - Alaska's Capital City Online Newspaper

And this one is not in English:

Observations and Experiments on the Ethology of the European Beaver "(castor Fiber L)"

books.google.com

I would find it helpful to pin down Richard Dawkins' views on this, since I generally consider him to be a source of credible and well thought out positions:

The Extended Phenotype - Wikipedia

en.wikipedia.org

Dawkins proposes there are three forms of extended phenotype. The first is the capacity of animals to modify their environment using architectural constructions, for which Dawkins provides as examples caddis houses and beaver dams.

Edit: I've never heard of a "caddis house."

Caddisflies are best known for the portable cases created by their larvae. About thirty families of caddisfly, members of the suborder Integripalpia, adopt this stratagem. These larvae eat detritus, largely decaying vegetable material, and the dead leaf fragments on which they feed tend to accumulate in hollows, in slow-moving sections of streams and behind stones and tree roots. The cases provide protection to the larvae as they make their way between these resources.^[25]

The case is a tubular structure made of silk, secreted from salivary glands near the mouth of the larva, and is started soon after the egg hatches. Various reinforcements may be incorporated into its structure, the nature of the materials and design depending on the larva's genetic makeup; this means that caddisfly larvae can be recognised by their cases down to family, and even genus level. The materials used include grains of sand, larger fragments of rock, bark, sticks, leaves, seeds and mollusc shells. These are neatly arranged and stuck onto the outer surface of the silken tube. As the larva grows, more material is added at the front, and the larva can turn round in the tube and trim the rear end so that it does not drag along the substrate.^[25]

Caddisfly cases are open at both ends, the larvae drawing oxygenated water through the posterior end, over their gills, and pumping it out of the wider, anterior end. The larvae move around inside the tubes and this helps maintain the water current; the lower the oxygen content of the water, the more active the larvae need to be. This mechanism enable caddisfly larvae to live in waters too low in oxygen content to support stonefly and mayfly larvae.^[22]

Yep, it seems likely that flowing water triggers the immediate action. By why is the reaction "build a dam" rather than "run away" like most other animals would do when "triggered" by something with which it is not familiar? It seems to me the deeper we look the more certain it is going to be that a significant amount of this is "instinct." Would a baby spider separated from its kind never build a web? I would think it would -- maybe not as good a web, but still a web.