You could likely extract and concatenate this data using a for loop or two, but a more elegent solution may be in using struct2cell(). Your fields will become a column vector of cells with their values being stored in a 3rd dimensional vector. From these, you could extract the data you're looking for using vertcat and brace indexing—See Below:
%% Setup:
bear = struct;
bear(1).paw = (1:100)';
bear(2).paw = (101:200)';
bear(3).paw = (201:300)';
bear(1).tail = (300:-1:201)';
bear(2).tail = (200:-1:101)';
bear(3).tail = (100:-1:1)';
%% Execution:
tempCell = struct2cell(bear);
vertPaw = vertcat(tempCell{1,1,:}); % Paw is the 1st row, 1st column entry of the cell array
vertTail = vertcat(tempCell{2,1,:}); % Tail is the 2nd row, 1st column entry of the cell array
horzVert = [vertPaw, vertTail]
