Series: The Three Little Ones (Tumikikuzusi)

A pair of first-time parent yukkuris learn the hard way that raising koyukkuris are difficult. Their first batch dies because they didn't pay close enough attention to them. Their second and third batch died because they paid too much attention to them, causing them to lack a sense of danger and accidentally kill themselves.

Last page implies that there'll be a continuation but looking at Tumikikuzusi's pixiv it doesn't seem like there's one