20 June, 2024

Today is at or around the solstice, so I figured it's time to do another observation of the week. In the month since the last observation summary (May 22), there have been nearly 1000 observations of Uta added to this site (914 according to iNat).

I just recently go caught up on identifications and have noticed that observations include many many many many hatchlings (by @nathanfrench, @kingmchris, @fran170, @lonnyholmes). In hand, or with a identifiable scale object in the picture, hatchlings can be recognized by size this time of year. Uta hatch at about 22-24 mm body length (from tip of nose to cloaca is called the snout-to-vent length...or just SVL). Beyond that there is a slight color difference between the head and body of Uta that is most pronounced at hatching, such as this observation (by @lonnyholmes). That is, hatchling Uta have this light milk chocolate color that differs from the gray of the body that is most vivid right after hatching. A third way to tell hatchlings without scale is their body:head proportions are just...off (such as here by @nathanfrench). Developmentally, most animals develop the head, eyes, brain early in development and may leave the rest of the body for later. In Uta hatchlings are born with a yolk plug of leftover yolk from the egg that sustains them the first three days or so before the gastro-intestinal tract is ready for them to feed. Hence, the head of hatchlings is much larger than should be for a body that size....just...off. It's a gestalt thing for sure.

In addition to early-season hatchlings entering the observation pool in the south, there continue to be numerous observations of copulations by @ishteva @chrisdellith) and even the occasional sighting of what is probably nesting (by @juan18346).

Where I've done work in the northern portions of their geographic distribution, females stop laying eggs around July 15 and I suspect it's the cessation on lengthening days that is the cue. It just takes them a while to get the message and finish up whatever part of the reproductive cycle they're in. Females with enlarged or yolked follicles right now (such as by @johnmartin @bobc) will finish that clutch, but it will take they 2-3 weeks to do so meaning the breeding season doesn't really end until mid-July. Afterwards females will all have this kind of spent look (by @fran170).

Despite all of the above really nice examples of various aspects of the breeding season, this week's observation of the week is this observation by @ishteva. The observation is of a female eating what looks to be a very large grasshopper with the abdomen still protruding out of her mouth. However, what makes the observation especially interesting is the male copulating with the female at the same time. Efficient.

As always, thank you to everyone who has observed a Side-blotched Lizards in the past few weeks. Your contributions are greatly appreciated.
—Pete Zani

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Posted on June 20, 2024 05:38 PM by petezani