Errata

1. In the abstract (p.1) and the discussion (p.12) sections, "70%" should be "78%", and "40%" should be "41%". The percentages in the results section are correct.

2. We found an error in the video selection and information recording subsection in the materials and methods section (p.4).

Error:
"Furthermore, the population of mountain gorillas (whether Bwindi or Virunga) were not identified in eleven videos and..."

Correct:
"Furthermore, the population of mountain gorillas (whether Bwindi or Virunga) were not identified in twelve videos and..."

3. We found errors in the data analysis subsection in the materials and methods section (p.5).

Error:
“Prior to the analysis, we excluded the 63 videos whose minimum distances were not estimated and coded as “NA”. We also excluded five videos whose main content was mating scenes of mountain gorillas because some of these mating videos obtained exceptional views, likes, and dislikes. Thereafter, eight videos were excluded because the number of subscribers was not available.”

Correct:
"Prior to the analysis, we excluded the 63 videos whose minimum distances were not estimated and coded as “NA”. We also excluded three videos whose main content was mating scenes of mountain gorillas because some of these mating videos obtained exceptional views, likes, and dislikes. Thereafter, two videos were excluded because the number of likes was not available, and then eight videos were excluded because the number of subscribers was not available.”

Supplementary explanation:
Step 1.
We excluded the 63 videos whose minimum distances were not estimated and coded as “NA”.

Step 2.
There were six (not five) videos that included mating scenes of mountain gorillas (Video ID = 2, 23, 38, 71, 191, 255, please also see the supplementary file entitled "S1 Dataset.xlxs"). We decided to exclude these videos because mating videos were rare and some of these mating videos obtained exceptional views, likes, and dislikes (e.g. Video ID = 2, 191). However, three out of six videos were already excluded in the previous step since these were coded as "NA" (Video ID = 2, 23, 255). Therefore, we excluded three mating videos in this step.

Step 3.
Besides, there were two videos whose number of likes was not available, and we excluded them from the analysis.

Step 4.
Finally, there were 12 videos whose number of subscribers was not available. However, three out of 12 videos were already excluded in the previous step since they were coded as “NA”. In addition, one video was already excluded in the previous step because its number of likes was not available (Please also see the supplementary file entitled “S1 Dataset.xlxs”). Therefore, we excluded eight videos in this step.

There is no change in the dataset we used in the following analysis.


4. In Table 1 - 4 and S2 and S3 Tables, the term "number of subscribes" should be "number of subscribers".

5. In Fig 3, "Humans and Gorillas (N=48)" should be "Humans and Gorillas (N=42)".

6. In the acknowledgments (p.16), the term "advises" should be "advice".

We apologize for these errors.