Even though in November, slime mold was still active.

It was already November and felt cold, so I didn't expect at all to find slime mold vigorously growing on the decayed logs in the mountains.

These are the immature fruiting bodies of the slime mold, but before talking about that, I would like to explain the circumstance that walking in the woods is becoming dangerous recently.

In 2025, Japan has seen a troubling rise in bear-related incidents across multiple regions, in particular, in north-east area of Honshu (the main island of Japan).

Asiatic black bears have been increasingly witnessed, and many fatal attacks have occurred in not only rural areas but residential areas in prefectures such as Akita, Iwate and Nagano.

In the area where I am living, a mountaineer was attacked by a bear and seriously injured in June this year while walking along mountain trail, and he was transported by a helicopter ambulance (Doctor Heli) to an emergency hospital. Fortunately, no personal injuries have occurred since then until now, although there is much information of eyewitness of bears including the nearby woods where I usually walk around.

The sign says: Beware of Bears. Don't enter into the mountains alone. Bring something that makes sound. If you meet a bear, don't make eye contact. If you witness a bear, report to the police.

So as a precaution, I have always carried something that make sound with me, such as a small radio and a bicycle bell fixed to a round stick.　Sometimes I shout loudly like voice training. 　 

However, there is also a theory that making loud noises or singing out loud can provoke bears and be dangerous.　I think it would be the best way not to go into the mountains, but that's difficult for me, and I wonder what I should do.

To get back to what I was saying earlier, when I went out in woods as usual to see if there were any stinkhorns (this mushroom emits very characteristic smell) in the afternoon the other day, I found that rotten logs that had previously been covered with white wood-decay fungus was now covered in yellow organism, so I took a closer look.

These are immature yellow fruiting bodies and plasmodium (amoeba) of a slime mold (probably Physarum rigidum).　They are densely emerging together.

Close-up photos. When immature, they are a beautiful yellow color.

This is an elongating plasmodium (amoeba).

November 2nd, 2025