Captive-bred Box Turtles Have No Natural 'Homing' Instinct?

[SouthTexasTurtleOwner]

Ok so most experienced turtle enthusiasts know that all turtles (terrestrial and sea) have a natural homing instinct and seem to know where they were born and have a natural instinct to be there or at least try and return there. In wild-caught American Box Turtles, this is especially true. What about captive-bred? If they are born in an enclosure or are rehomed, are there conclusive studies suggesting they lack this natural homing instinct?

 

[Tom]

Ok so most experienced turtle enthusiasts know that all turtles (terrestrial and sea) have a natural homing instinct and seem to know where they were born and have a natural instinct to be there or at least try and return there. In wild-caught American Box Turtles, this is especially true. What about captive-bred? If they are born in an enclosure or are rehomed, are there conclusive studies suggesting they lack this natural homing instinct?

Who is going to go turn their turtle that they've raised for years loose to see if it comes home?

Where would be "home"? The incubator? The indoor tank? The outdoor enclosure?

Neat concept, but I don't know how you'd study it practically with out terrible risks.

 

[ZenHerper]

In order to study this properly, among other things, you'd need:

*a very refined outline of what wild animals are actually sensing, intending, doing

*strict control of breeding, incubating, rearing conditions (indoors? outdoors? etc.)

*cooperation from a state to release CBs

*gps trackers on all animals

*lots of time on your hands to spend watching the little dots noodle around all day, indefinitely (so, tracking/data analysis tech)

*high tolerance for loss of test subjects to predation, cars, accidents, toxins, illness, etc..

 

[SouthTexasTurtleOwner]

Good replies and I appreciate them. I understand basic scientific research. For the reasons, I'll take it that there are not known studies that have been done on the issue.

 

[ZenHerper]

Good replies and I appreciate them. I understand basic scientific research. For the reasons, I'll take it that there are not known studies that have been done on the issue.

Well, we'd have to be 100% certain what wild populations are doing and by what mechanism(s). And since Chelonians are not a monolith, we'd have to clarify all the deets by species.

Anecdote: I had a WC EBT as a child. Kids from another part of town had brought him to me from a wooded area (he was missing an eye and a foot). In temperate weather, he spent a good deal of time in the back yard. Though he had favorite spots to sun and shade, he never took off in the direction of "Home".

So...was him "homing instinct" broken? Consciously disregarded/overridden because he found a nice territory with all the amenities (except for sex)? Is the Homing Instinct Theory flawed in some fundamental way? Or do some mechanisms apply to one species and not across all?

I think there are still lots of questions that have to be answered for wild populations (by species) before we can imagine how to design meaningful studies for captive clutches.

 

[SouthTexasTurtleOwner]

Indeed and you make many valid points about studies and especially the wild-caught injured EBT in your posting. Although this is completely anecdotal, I will describe my experience. I am a hobbyist/enthusiast and do not raise for selling, I have 6 EBTs and 2 OBTs all living in a huge outdoor enclosure year round. The EBT matriarch was rehomed (likely wild-caught) to me 7 years ago with the remaining 5 EBTs being her captive-bred offspring. The OBTs were rehomed as hatchlings but captive-bred as well. All captive-bred specimens of both species are quite content year-round and growing well. The EBT matriarch, while extremely healthy herself, is the only one out of the entire bunch who continually tries to escape. Its fairly obvious her instincts are pointing her elsewhere. Again, while this is anecdotal, it does seem to point to distinct homing differences between captive-bred's and wild-caught.

 

[Relic]

I've got some box turtles that take great delight in discovering what lies beyond the borders of their pen, and will move heaven and earth and unsecured iron gates to reach the other side - both wild caught (30+ years) and their progeny.

I've got some box turtles that have no interest whatsoever in the outside world - both wild caught (30+ years) and their progeny.

I've discerned no rhyme or reason or pattern. And if it is proven to be some indwelling homing instinct, it is totally broken in some specimens.

 

[ZenHerper]

Indeed and you make many valid points about studies and especially the wild-caught injured EBT in your posting. Although this is completely anecdotal, I will describe my experience. I am a hobbyist/enthusiast and do not raise for selling, I have 6 EBTs and 2 OBTs all living in a huge outdoor enclosure year round. The EBT matriarch was rehomed (likely wild-caught) to me 7 years ago with the remaining 5 EBTs being her captive-bred offspring. The OBTs were rehomed as hatchlings but captive-bred as well. All captive-bred specimens of both species are quite content year-round and growing well. The EBT matriarch, while extremely healthy herself, is the only one out of the entire bunch who continually tries to escape. Its fairly obvious her instincts are pointing her elsewhere. Again, while this is anecdotal, it does seem to point to distinct homing differences between captive-bred's and wild-caught.

But the only way to know if she is experiencing a Homing Instinct would be to release her, track her, and see if she does indeed Return Home (let's assume we know where she came from).

She may merely dislike your boundaries. Wild territories are quite large, after all. Her previous lived experience is of unbounded landscape(s), and the ability to choose her own mates and nesting sites. Your CBs only know what they know: circumscribed territory with all amenities included.

We simply do not know enough about what the supposed Homing Instinct is, and how it differs from garden-variety interaction of physical senses with memory and the desire to find unrelated mates.

What sea turtles do is more migratory...they travel between feeding and mating territories in predictable cycles (pretty much what our species did just prior to the Neolithic Age). I hesitate to call this "Homing", as they are as at Home at any stage along the cycle. Just as migrating geese are at Home in Canada, in New Jersey, or in Florida. And birds are not born with the entire knowledge...they do learn how to go back and forth. I'm going to imagine that 'flocks' of sea turtles have conscious components to their travels as well.

The proper First study would involve identifying as many WC turtles as possible, tagging them, and releasing them. Do they actually Go Home to try and reestablish themselves on their past territories?

 

[mark1]

The proper First study would involve identifying as many WC turtles as possible, tagging them, and releasing them. Do they actually Go Home to try and reestablish themselves on their past territories?

this has been done …..

 

[ZenHerper]

this has been done …..

Twenty turtles is not a study. It just isn't. lol

And any collected data has yet to be linked to actual brain centers and activity of neuron clusters. There has not been any proposed mechanism. Are they keying off the sun? Movement of weather systems? Magnetic fields? Sense of smell? And what are the things that might explain disruptions of these mechanisms?

The concept "Homing Instinct" is very inexact.

We need the degree of detail that we have for birds:

Behavioral and Neural Mechanisms of Homing and Migration in Birds

The Avian Hippocampus, Homing in Pigeons and the Memory Representation of Large-Scale Space

The extraordinary navigational ability of homing pigeons provides a unique spatial cognitive system to investigate how the brain is able to represent past experiences as memory. In this paper, we first summarize a large body of lesion data in an attempt to characterize the role of the avian...

scholarworks.bgsu.edu

If we have this kind of data for box turtles, I would eagerly examine it! =))

 

[Maggie3fan]

Some food for thought...(simplified)our US Air Force wanted to use the territory of the California Desert tort (Gopherus agassizii) in the Mojave...so they moved thousands or hundreds of thousands of the tortoises, little realizing that those tortoises are extremely territorial and most died trying to get 'home'...

 

[mark1]

If we have this kind of data for box turtles, I would eagerly examine it! =))

https://scholar.google.com/scholar?hl=en&as_sdt=0,36&q=homing+instinct+turtles+&btnG=

https://scholar.google.com/scholar?hl=en&as_sdt=0,36&q=turtle++homing+ability&btnG=

https://scholar.google.com/scholar?hl=en&as_sdt=0,36&q=box+turtle++homing+ability&btnG=
https://scholar.google.com/scholar?hl=en&as_sdt=0,36&q=box+turtle++homing+ability&btnG=


https://scholar.google.com/scholar?hl=en&as_sdt=0,36&q=tortoise+homing+ability&btnG=

https://scholar.google.com/scholar?...ta+homing+ability&oq=homing+instinct+turtles+

 

[Madame Terrapene]

More anecdotal musings here based off of observations: my guess is that since they're creatures of habit (especially the adults), they're just attempting to return to their original territory when they're "homing". Captive-bred may less aggressively try to return "home" if they're used to being shuffled between enclosures, but that's probably turtle-dependent as some turtles are definitely more accepting of new environments than others. Since they're diurnal, I'm betting, they navigate using landmarks and the sun, but who knows. I can imagine an adult being released into some strange area, wandering around for a bit looking for "home", then realizing that they're lost and hauling off in the direction that they think home is. Whether or not they have some other non-visual method of homing is beyond me, but please share here if you are aware of one.

Of note, I've read that juveniles move significantly smaller distances when released than adults, which to me makes sense since part of growing up as a box turtle is establishing a home range. Once a juvenile figures out where the food, shelter and water is, I doubt they'd have a strong urge to travel many more miles to see the world unless there's a local pressure to move (habitat loss, too many predators, not enough ladies etc).

Since we're posting links:

Head-started EBTs (w/ satellite image of winter hibernacula locations, shows home range establishment by headstarted juveniles) https://scholarscompass.vcu.edu/cgi/viewcontent.cgi?article=1643&context=etd

Head-started ornates https://pdfs.semanticscholar.org/2c37/575bf2679deb0761775bcd935a9b4c81834e.pdf

 

[SouthTexasTurtleOwner]

Thank you Madame Terrapene, very interesting and I have begun studying the citations you provided. I learn new stuff every day!