The gaur is one of the largest extant bovids. It is a strong and massively built bovine with a high convex ridge on the forehead between the horns, which protrudes anteriorly, causing a deep hollow in the profile of the upper part of the head. There is a prominent ridge on the back. They have a distinct ridge running from the shoulders to the middle of the back; the shoulders may be as much as higher than the rump. This ridge is caused by the great length of the spinous processes of the vertebrae of the fore-part of the trunk as compared with those of the loins. Both sexes have horns, which grow from the sides of the head, curving upwards. The horns are decidedly flattened at the base and regularly curved throughout their length, and are bent inward and slightly backward at their tips. Yet, tigers have successfully taken on adult gaur bulls as per the following :
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.595.6296&rep=rep1&type=pdf
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.691.6934&rep=rep1&type=pdf
https://archive.org/details/PredatorsAndPrey-K.UllasKaranth/page/n27
https://www.cms.int/sites/default/files/document/ScC16_Doc_19_Rev2_Draft_Proposals_Tiger_Eonly_0.pdf
https://www.researchgate.net/publication/327248826_Bos_frontalis_and_Bos_gaurus_Artiodactyla_Bovidae
https://www.jstor.org/stable/5647
https://onlinelibrary.wiley.com/doi/full/10.1002/ece3.6268
https://archive.org/details/tigers00rhva
https://archive.org/details/vanishingtigerwi0000sinh
https://www.researchgate.net/publication/292937817_Gaur_bos_gaurus_C_H_Smith_1827