Why aren't there HiRISE observation footprints near the Martian poles?

Browsing the HiRISE observations of Mars, I noticed that there aren't any observation footprints at a latitude lower than -65° or higher than 65°. Why is this? Is there something I am not seeing? Is there a technical reason why these observations can't be done at the high latitudes?

Image centered near 65.698°, 328.230°E. Red ticks are HiRISE observations and yellow are HiRISE suggestions.

Disclaimer: I didn't look at the entire map, but I did look at a few different longitudes to see if the 65° limit was consistent across the planet.

• Interesting! MRO's inclination is 93 degrees so that's not an explanation. – uhoh Jul 17 at 1:45