25-hour days.

As another poster already said, there will be 25-hour days at some time.

The dinosaurs had days with fewer hours than us.

Where there fewer hours or were those hours just different length?

Now we have locked in second extremely hard underpinning all of our measurements. But you could consider that you have same number of hours in a day and length of those hours has changed...

You could look at it either way. I couldn't say which system the dinosaurs actually used.

I have it on good authority they just used unixtime for everyone but put all the leapseconds in the tz table.

A Martian sol (day cycle/rotation) is > 24 hours (by about 40 minutes). Locked in seconds seems to be the easiest for general use mathematically. 24 hours in a day is a bit of a leftover from sundials and 12 being one of the easiest large fractions of a circle and the Earth day was never really a universal anyway, just an accident of where and roughly when we lived. On the other hand, the modern metric second is now defined at exactly 9,192,631,770 periods of Cesium-133 for atomic clocks and other reasons, so a locked second is useful for a lot of reasons.