That’s debatable, I feel like spiders design their webs.
do they understand they might try other patterns, and actively choose the one they use?
I don’t know what their cognitive processes are, but it seems unlikely they do. It still sounds perfectly normal to me to say the following:
“Spider webs are designed to be safe for the spider, but still trap as much potential prey as possible.”
Does that really hit your ear (eye) wrong?
yes. i would talk about the evolutionary pressures that have shaped the behavior of the organism. i wouldn’t impart volition to them.
How would you phrase it? (Honest question)
“spiders have evolved to produce webs. evolutionary pressures have favored species which produce webs that are safe for the organism and effective at trapping enough prey to maintain the life and reproductive cycles of the organism.”
That feels much more formal to me. Definitely not incorrect, but not how I’d explain it casually to someone.
devoid of context, your phrasing might be fine. in this context, precision is important for us to focus on the actual issue.
I don’t really think “milk customized for a calf” makes much of a difference for the point OP was making. Sorry, if this was kind of a waste of time, I just love that milk changes composition based on the baby’s situation and then got really interested in the linguistic limits of “design.”