Nature Cat actually started in late 2014. The reason why it did not air until November 2015 was that they had
to make a WHOLE season first. The episodes that are the piolet are not lost, the real dates are what is lost. My friend works with PBS and he told me this.
Heartthrob Hamster/Astronuts was made October 24th 2014
Stream and Shout/Hal's Day Off was made November 1st 2014
And the rest of the episodes in December 2014
The second season took place before Thanksgiving in 2015
The original idea was for Heartthrob Hamster to be a 22 minute long episode called "The Adventures of Nature Cat" but that didn't work out. The animation is different in Heartthrob Hamster as well.